ComboBox.FindStringExact Método
Definición
Importante
Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.
Busca el elemento que coincide exactamente con la cadena especificada.
Sobrecargas
| FindStringExact(String) |
Busca el primer elemento del cuadro combinado que coincide con la cadena especificada. |
| FindStringExact(String, Int32) |
Busca el primer elemento situado detrás del índice dado que coincide con la cadena especificada. |
FindStringExact(String)
Busca el primer elemento del cuadro combinado que coincide con la cadena especificada.
public:
int FindStringExact(System::String ^ s);public int FindStringExact (string s);public int FindStringExact (string? s);member this.FindStringExact : string -> intPublic Function FindStringExact (s As String) As IntegerParámetros
Devoluciones
Índice de base cero del primer elemento encontrado; devuelve -1 si no hay coincidencias o 0 si el parámetro s indica Empty.
Ejemplos
En el ejemplo de código siguiente se muestra cómo inicializar un ComboBox control estableciendo las MaxDropDownItems propiedades y DropDownStyle y utilizando los FindStringExact métodos para buscar en ComboBox. También muestra el control del SelectedIndexChanged evento.
#using <System.Drawing.dll>
#using <System.dll>
#using <System.Windows.Forms.dll>
using namespace System::Windows::Forms;
using namespace System;
public ref class Form1: public System::Windows::Forms::Form
{
public:
Form1() : Form()
{
InitializeComboBox();
InitializeTextBox();
this->Label1 = gcnew System::Windows::Forms::Label;
this->SuspendLayout();
this->Label1->Location = System::Drawing::Point( 8, 24 );
this->Label1->Name = "Label1";
this->Label1->Size = System::Drawing::Size( 120, 32 );
this->Label1->TabIndex = 1;
this->Label1->Text = "Use drop-down to choose a name:";
this->Label1->TextAlign = System::Drawing::ContentAlignment::MiddleRight;
this->ClientSize = System::Drawing::Size( 292, 266 );
this->Controls->Add( this->Label1 );
this->Name = "Form1";
this->Text = "Form1";
this->ResumeLayout( false );
}
internal:
System::Windows::Forms::Label ^ Label1;
// Declare and initialize the text box.
internal:
// This text box text will be update programmatically. The user is not
// allowed to update it, so the ReadOnly property is set to true.
System::Windows::Forms::TextBox^ TextBox1;
private:
void InitializeTextBox()
{
this->TextBox1 = gcnew System::Windows::Forms::TextBox;
this->TextBox1->ScrollBars = ScrollBars::Vertical;
this->TextBox1->Location = System::Drawing::Point( 64, 128 );
this->TextBox1->Multiline = true;
this->TextBox1->Name = "TextBox1";
this->TextBox1->ReadOnly = true;
this->TextBox1->Size = System::Drawing::Size( 184, 120 );
this->TextBox1->TabIndex = 4;
this->TextBox1->Text = "Employee and Number of Awards:";
this->Controls->Add( this->TextBox1 );
}
// Declare comboBox1 as a ComboBox.
internal:
System::Windows::Forms::ComboBox^ ComboBox1;
private:
// This method initializes the combo box, adding a large string array
// but limiting the drop-down size to six rows so the combo box doesn't
// cover other controls when it expands.
void InitializeComboBox()
{
this->ComboBox1 = gcnew System::Windows::Forms::ComboBox;
array<String^>^ employees = {"Hamilton, David","Hensien, Kari",
"Hammond, Maria","Harris, Keith","Henshaw, Jeff D.",
"Hanson, Mark","Harnpadoungsataya, Sariya",
"Harrington, Mark","Harris, Keith","Hartwig, Doris",
"Harui, Roger","Hassall, Mark","Hasselberg, Jonas",
"Harnpadoungsataya, Sariya","Henshaw, Jeff D.",
"Henshaw, Jeff D.","Hensien, Kari","Harris, Keith",
"Henshaw, Jeff D.","Hensien, Kari","Hasselberg, Jonas",
"Harrington, Mark","Hedlund, Magnus","Hay, Jeff",
"Heidepriem, Brandon D."};
ComboBox1->Items->AddRange( employees );
this->ComboBox1->Location = System::Drawing::Point( 136, 32 );
this->ComboBox1->IntegralHeight = false;
this->ComboBox1->MaxDropDownItems = 5;
this->ComboBox1->DropDownStyle = ComboBoxStyle::DropDownList;
this->ComboBox1->Name = "ComboBox1";
this->ComboBox1->Size = System::Drawing::Size( 136, 81 );
this->ComboBox1->TabIndex = 0;
this->Controls->Add( this->ComboBox1 );
// Associate the event-handling method with the
// SelectedIndexChanged event.
this->ComboBox1->SelectedIndexChanged +=
gcnew System::EventHandler( this, &Form1::ComboBox1_SelectedIndexChanged );
}
private:
// This method is called when the user changes his or her selection.
// It searches for all occurrences of the selected employee's
// name in the Items array and adds the employee's name and
// the number of occurrences to TextBox1.Text.
// CAUTION This code exposes a known bug: If the index passed to the
// FindStringExact(searchString, index) method is the last index
// of the array, the code throws an exception.
void ComboBox1_SelectedIndexChanged( Object^ sender,
System::EventArgs^ e )
{
ComboBox^ comboBox = (ComboBox^)(sender);
// Save the selected employee's name, because we will remove
// the employee's name from the list.
String^ selectedEmployee = (String^)(ComboBox1->SelectedItem);
int count = 0;
int resultIndex = -1;
// Call the FindStringExact method to find the first
// occurrence in the list.
resultIndex = ComboBox1->FindStringExact( selectedEmployee );
// Remove the name as it is found, and increment the found count.
// Then call the FindStringExact method again, passing in the
// index of the current found item so the search starts there
// instead of at the beginning of the list.
while ( resultIndex != -1 )
{
ComboBox1->Items->RemoveAt( resultIndex );
count += 1;
resultIndex = ComboBox1->FindStringExact( selectedEmployee,
resultIndex );
}
TextBox1->Text = TextBox1->Text + "\r\n" + selectedEmployee + ": " +
count;
}
};
int main()
{
Application::Run( gcnew Form1 );
}
using System.Windows.Forms;
public class Form1:
System.Windows.Forms.Form
{
public Form1() : base()
{
InitializeComboBox();
InitializeTextBox();
this.Label1 = new System.Windows.Forms.Label();
this.SuspendLayout();
this.Label1.Location = new System.Drawing.Point(8, 24);
this.Label1.Name = "Label1";
this.Label1.Size = new System.Drawing.Size(120, 32);
this.Label1.TabIndex = 1;
this.Label1.Text = "Use drop-down to choose a name:";
this.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleRight;
this.ClientSize = new System.Drawing.Size(292, 266);
this.Controls.Add(this.Label1);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
}
public static void Main()
{
Application.Run(new Form1());
}
internal System.Windows.Forms.Label Label1;
// Declare and initialize the text box.
// This text box text will be update programmatically. The user is not
// allowed to update it, so the ReadOnly property is set to true.
internal System.Windows.Forms.TextBox TextBox1;
private void InitializeTextBox()
{
this.TextBox1 = new System.Windows.Forms.TextBox();
this.TextBox1.ScrollBars = ScrollBars.Vertical;
this.TextBox1.Location = new System.Drawing.Point(64, 128);
this.TextBox1.Multiline = true;
this.TextBox1.Name = "TextBox1";
this.TextBox1.ReadOnly = true;
this.TextBox1.Size = new System.Drawing.Size(184, 120);
this.TextBox1.TabIndex = 4;
this.TextBox1.Text = "Employee and Number of Awards:";
this.Controls.Add(this.TextBox1);
}
// Declare comboBox1 as a ComboBox.
internal System.Windows.Forms.ComboBox ComboBox1;
// This method initializes the combo box, adding a large string array
// but limiting the drop-down size to six rows so the combo box doesn't
// cover other controls when it expands.
private void InitializeComboBox()
{
this.ComboBox1 = new System.Windows.Forms.ComboBox();
string[] employees = new string[]{"Hamilton, David", "Hensien, Kari",
"Hammond, Maria", "Harris, Keith", "Henshaw, Jeff D.",
"Hanson, Mark", "Harnpadoungsataya, Sariya",
"Harrington, Mark", "Harris, Keith", "Hartwig, Doris",
"Harui, Roger", "Hassall, Mark", "Hasselberg, Jonas",
"Harnpadoungsataya, Sariya", "Henshaw, Jeff D.",
"Henshaw, Jeff D.", "Hensien, Kari", "Harris, Keith",
"Henshaw, Jeff D.", "Hensien, Kari", "Hasselberg, Jonas",
"Harrington, Mark", "Hedlund, Magnus", "Hay, Jeff",
"Heidepriem, Brandon D."};
ComboBox1.Items.AddRange(employees);
this.ComboBox1.Location = new System.Drawing.Point(136, 32);
this.ComboBox1.IntegralHeight = false;
this.ComboBox1.MaxDropDownItems = 5;
this.ComboBox1.DropDownStyle = ComboBoxStyle.DropDownList;
this.ComboBox1.Name = "ComboBox1";
this.ComboBox1.Size = new System.Drawing.Size(136, 81);
this.ComboBox1.TabIndex = 0;
this.Controls.Add(this.ComboBox1);
// Associate the event-handling method with the
// SelectedIndexChanged event.
this.ComboBox1.SelectedIndexChanged +=
new System.EventHandler(ComboBox1_SelectedIndexChanged);
}
// This method is called when the user changes his or her selection.
// It searches for all occurrences of the selected employee's
// name in the Items array and adds the employee's name and
// the number of occurrences to TextBox1.Text.
// CAUTION This code exposes a known bug: If the index passed to the
// FindStringExact(searchString, index) method is the last index
// of the array, the code throws an exception.
private void ComboBox1_SelectedIndexChanged(object sender,
System.EventArgs e)
{
ComboBox comboBox = (ComboBox) sender;
// Save the selected employee's name, because we will remove
// the employee's name from the list.
string selectedEmployee = (string) ComboBox1.SelectedItem;
int count = 0;
int resultIndex = -1;
// Call the FindStringExact method to find the first
// occurrence in the list.
resultIndex = ComboBox1.FindStringExact(selectedEmployee);
// Remove the name as it is found, and increment the found count.
// Then call the FindStringExact method again, passing in the
// index of the current found item so the search starts there
// instead of at the beginning of the list.
while (resultIndex!=-1)
{
ComboBox1.Items.RemoveAt(resultIndex);
count += 1;
resultIndex = ComboBox1.FindStringExact(selectedEmployee,
resultIndex);
}
// Update the text in Textbox1.
TextBox1.Text = TextBox1.Text+ "\r\n" + selectedEmployee + ": "
+ count;
}
}
Imports System.Windows.Forms
Public Class Form1
Inherits System.Windows.Forms.Form
Public Sub New()
MyBase.New()
InitializeComboBox()
InitializeTextBox()
Me.Label1 = New System.Windows.Forms.Label
Me.SuspendLayout()
Me.Label1.Location = New System.Drawing.Point(8, 24)
Me.Label1.Name = "Label1"
Me.Label1.Size = New System.Drawing.Size(120, 32)
Me.Label1.TabIndex = 1
Me.Label1.Text = "Use drop-down to choose a name:"
Me.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleRight
Me.ClientSize = New System.Drawing.Size(292, 266)
Me.Controls.Add(Me.Label1)
Me.Name = "Form1"
Me.Text = "Form1"
Me.ResumeLayout(False)
End Sub
Shared Sub Main()
Application.Run(New Form1)
End Sub
Friend WithEvents Label1 As System.Windows.Forms.Label
' Declare and initialize the text box.
' This text box text will be update programmatically. The user is not
' allowed to update it, so the ReadOnly property is set to true.
Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
Private Sub InitializeTextBox()
Me.TextBox1 = New System.Windows.Forms.TextBox
Me.TextBox1.ScrollBars = ScrollBars.Vertical
Me.TextBox1.Location = New System.Drawing.Point(64, 128)
Me.TextBox1.Multiline = True
Me.TextBox1.Name = "TextBox1"
Me.TextBox1.ReadOnly = True
Me.TextBox1.Size = New System.Drawing.Size(184, 120)
Me.TextBox1.TabIndex = 4
Me.TextBox1.Text = "Employee and Number of Awards:"
Me.Controls.Add(Me.TextBox1)
End Sub
' Declare comboBox1 as a ComboBox.
Friend WithEvents ComboBox1 As System.Windows.Forms.ComboBox
' This method initializes the combo box, adding a large string
' array but limiting the drop-down size to six rows so the combo box
' doesn't cover other controls when it expands.
Private Sub InitializeComboBox()
Me.ComboBox1 = New System.Windows.Forms.ComboBox
Dim employees() As String = New String() {"Hamilton, David", _
"Hensien, Kari", "Hammond, Maria", "Harris, Keith", _
"Henshaw, Jeff D.", "Hanson, Mark", "Harnpadoungsataya, Sariya", _
"Harrington, Mark", "Harris, Keith", "Hartwig, Doris", _
"Harui, Roger", "Hassall, Mark", "Hasselberg, Jonas", _
"Harnpadoungsataya, Sariya", "Henshaw, Jeff D.", "Henshaw, Jeff D.", _
"Hensien, Kari", "Harris, Keith", "Henshaw, Jeff D.", _
"Hensien, Kari", "Hasselberg, Jonas", "Harrington, Mark", _
"Hedlund, Magnus", "Hay, Jeff", "Heidepriem, Brandon D."}
ComboBox1.Items.AddRange(employees)
Me.ComboBox1.Location = New System.Drawing.Point(136, 32)
Me.ComboBox1.IntegralHeight = False
Me.ComboBox1.MaxDropDownItems = 5
Me.ComboBox1.DropDownStyle = ComboBoxStyle.DropDown
Me.ComboBox1.Name = "ComboBox1"
Me.ComboBox1.Size = New System.Drawing.Size(136, 81)
Me.ComboBox1.TabIndex = 0
Me.Controls.Add(Me.ComboBox1)
End Sub
' This method is called when the user changes his or her selection.
' It searches for all occurrences of the selected employee's
' name in the Items array and adds the employee's name and
' the number of occurrences to TextBox1.Text.
' CAUTION This code exposes a known bug: If the index passed to the
' FindStringExact(searchString, index) method is the last index
' of the array, the code throws an exception.
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As Object, _
ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
Dim comboBox As comboBox = CType(sender, comboBox)
' Save the selected employee's name, because we will remove
' the employee's name from the list.
Dim selectedEmployee = CType(ComboBox1.SelectedItem, String)
Dim count As Integer = 0
Dim resultIndex As Integer = -1
' Call the FindStringExact method to find the first
' occurrence in the list.
resultIndex = ComboBox1.FindStringExact(ComboBox1.SelectedItem)
' Remove the name as it is found, and increment the found count.
' Then call the FindStringExact method again, passing in the index of the
' current found item so the search starts there instead of
' at the beginning of the list.
While (resultIndex <> -1)
ComboBox1.Items.RemoveAt(resultIndex)
count += 1
resultIndex = ComboBox1.FindStringExact _
(selectedEmployee, resultIndex)
End While
' Update the text in Textbox1.
TextBox1.Text = TextBox1.Text & Microsoft.VisualBasic.vbCrLf _
& selectedEmployee & ": " & count
End Sub
End Class
Comentarios
La búsqueda realizada por este método no distingue mayúsculas de minúsculas. El s parámetro es una cadena que se compara con el texto asociado a los elementos de la lista de cuadros combinados. La búsqueda busca una coincidencia a partir del principio del texto y devuelve el primer elemento de la lista que coincide con la subcadena especificada. A continuación, puede realizar tareas, como quitar el elemento que contiene el texto de búsqueda mediante el Remove método o cambiar el texto del elemento. Una vez que haya encontrado el texto especificado, si desea buscar otras instancias del texto en ComboBox, debe usar la versión del FindStringExact método que proporciona un parámetro para especificar un índice inicial dentro de ComboBox. Si desea realizar una búsqueda parcial de palabras en lugar de una coincidencia exacta de palabras, use el FindString método .
Se aplica a
FindStringExact(String, Int32)
Busca el primer elemento situado detrás del índice dado que coincide con la cadena especificada.
public:
int FindStringExact(System::String ^ s, int startIndex);public int FindStringExact (string s, int startIndex);public int FindStringExact (string? s, int startIndex);member this.FindStringExact : string * int -> intPublic Function FindStringExact (s As String, startIndex As Integer) As IntegerParámetros
- startIndex
- Int32
Índice de base cero del elemento situado delante del primer elemento que se va a buscar. Se establece en -1 para buscar desde el principio del control.
Devoluciones
Índice de base cero del primer elemento encontrado; devuelve -1 si no hay coincidencias o 0 si el parámetro s indica Empty.
Excepciones
startIndex es menor que -1.
o bien
startIndex es igual que el último índice de la colección.
Ejemplos
En el ejemplo de código siguiente se muestra cómo inicializar un ComboBox control estableciendo las MaxDropDownItems propiedades y DropDownStyle y utilizando los FindStringExact métodos para buscar en ComboBox. También muestra el control del SelectedIndexChanged evento.
#using <System.Drawing.dll>
#using <System.dll>
#using <System.Windows.Forms.dll>
using namespace System::Windows::Forms;
using namespace System;
public ref class Form1: public System::Windows::Forms::Form
{
public:
Form1() : Form()
{
InitializeComboBox();
InitializeTextBox();
this->Label1 = gcnew System::Windows::Forms::Label;
this->SuspendLayout();
this->Label1->Location = System::Drawing::Point( 8, 24 );
this->Label1->Name = "Label1";
this->Label1->Size = System::Drawing::Size( 120, 32 );
this->Label1->TabIndex = 1;
this->Label1->Text = "Use drop-down to choose a name:";
this->Label1->TextAlign = System::Drawing::ContentAlignment::MiddleRight;
this->ClientSize = System::Drawing::Size( 292, 266 );
this->Controls->Add( this->Label1 );
this->Name = "Form1";
this->Text = "Form1";
this->ResumeLayout( false );
}
internal:
System::Windows::Forms::Label ^ Label1;
// Declare and initialize the text box.
internal:
// This text box text will be update programmatically. The user is not
// allowed to update it, so the ReadOnly property is set to true.
System::Windows::Forms::TextBox^ TextBox1;
private:
void InitializeTextBox()
{
this->TextBox1 = gcnew System::Windows::Forms::TextBox;
this->TextBox1->ScrollBars = ScrollBars::Vertical;
this->TextBox1->Location = System::Drawing::Point( 64, 128 );
this->TextBox1->Multiline = true;
this->TextBox1->Name = "TextBox1";
this->TextBox1->ReadOnly = true;
this->TextBox1->Size = System::Drawing::Size( 184, 120 );
this->TextBox1->TabIndex = 4;
this->TextBox1->Text = "Employee and Number of Awards:";
this->Controls->Add( this->TextBox1 );
}
// Declare comboBox1 as a ComboBox.
internal:
System::Windows::Forms::ComboBox^ ComboBox1;
private:
// This method initializes the combo box, adding a large string array
// but limiting the drop-down size to six rows so the combo box doesn't
// cover other controls when it expands.
void InitializeComboBox()
{
this->ComboBox1 = gcnew System::Windows::Forms::ComboBox;
array<String^>^ employees = {"Hamilton, David","Hensien, Kari",
"Hammond, Maria","Harris, Keith","Henshaw, Jeff D.",
"Hanson, Mark","Harnpadoungsataya, Sariya",
"Harrington, Mark","Harris, Keith","Hartwig, Doris",
"Harui, Roger","Hassall, Mark","Hasselberg, Jonas",
"Harnpadoungsataya, Sariya","Henshaw, Jeff D.",
"Henshaw, Jeff D.","Hensien, Kari","Harris, Keith",
"Henshaw, Jeff D.","Hensien, Kari","Hasselberg, Jonas",
"Harrington, Mark","Hedlund, Magnus","Hay, Jeff",
"Heidepriem, Brandon D."};
ComboBox1->Items->AddRange( employees );
this->ComboBox1->Location = System::Drawing::Point( 136, 32 );
this->ComboBox1->IntegralHeight = false;
this->ComboBox1->MaxDropDownItems = 5;
this->ComboBox1->DropDownStyle = ComboBoxStyle::DropDownList;
this->ComboBox1->Name = "ComboBox1";
this->ComboBox1->Size = System::Drawing::Size( 136, 81 );
this->ComboBox1->TabIndex = 0;
this->Controls->Add( this->ComboBox1 );
// Associate the event-handling method with the
// SelectedIndexChanged event.
this->ComboBox1->SelectedIndexChanged +=
gcnew System::EventHandler( this, &Form1::ComboBox1_SelectedIndexChanged );
}
private:
// This method is called when the user changes his or her selection.
// It searches for all occurrences of the selected employee's
// name in the Items array and adds the employee's name and
// the number of occurrences to TextBox1.Text.
// CAUTION This code exposes a known bug: If the index passed to the
// FindStringExact(searchString, index) method is the last index
// of the array, the code throws an exception.
void ComboBox1_SelectedIndexChanged( Object^ sender,
System::EventArgs^ e )
{
ComboBox^ comboBox = (ComboBox^)(sender);
// Save the selected employee's name, because we will remove
// the employee's name from the list.
String^ selectedEmployee = (String^)(ComboBox1->SelectedItem);
int count = 0;
int resultIndex = -1;
// Call the FindStringExact method to find the first
// occurrence in the list.
resultIndex = ComboBox1->FindStringExact( selectedEmployee );
// Remove the name as it is found, and increment the found count.
// Then call the FindStringExact method again, passing in the
// index of the current found item so the search starts there
// instead of at the beginning of the list.
while ( resultIndex != -1 )
{
ComboBox1->Items->RemoveAt( resultIndex );
count += 1;
resultIndex = ComboBox1->FindStringExact( selectedEmployee,
resultIndex );
}
TextBox1->Text = TextBox1->Text + "\r\n" + selectedEmployee + ": " +
count;
}
};
int main()
{
Application::Run( gcnew Form1 );
}
using System.Windows.Forms;
public class Form1:
System.Windows.Forms.Form
{
public Form1() : base()
{
InitializeComboBox();
InitializeTextBox();
this.Label1 = new System.Windows.Forms.Label();
this.SuspendLayout();
this.Label1.Location = new System.Drawing.Point(8, 24);
this.Label1.Name = "Label1";
this.Label1.Size = new System.Drawing.Size(120, 32);
this.Label1.TabIndex = 1;
this.Label1.Text = "Use drop-down to choose a name:";
this.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleRight;
this.ClientSize = new System.Drawing.Size(292, 266);
this.Controls.Add(this.Label1);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
}
public static void Main()
{
Application.Run(new Form1());
}
internal System.Windows.Forms.Label Label1;
// Declare and initialize the text box.
// This text box text will be update programmatically. The user is not
// allowed to update it, so the ReadOnly property is set to true.
internal System.Windows.Forms.TextBox TextBox1;
private void InitializeTextBox()
{
this.TextBox1 = new System.Windows.Forms.TextBox();
this.TextBox1.ScrollBars = ScrollBars.Vertical;
this.TextBox1.Location = new System.Drawing.Point(64, 128);
this.TextBox1.Multiline = true;
this.TextBox1.Name = "TextBox1";
this.TextBox1.ReadOnly = true;
this.TextBox1.Size = new System.Drawing.Size(184, 120);
this.TextBox1.TabIndex = 4;
this.TextBox1.Text = "Employee and Number of Awards:";
this.Controls.Add(this.TextBox1);
}
// Declare comboBox1 as a ComboBox.
internal System.Windows.Forms.ComboBox ComboBox1;
// This method initializes the combo box, adding a large string array
// but limiting the drop-down size to six rows so the combo box doesn't
// cover other controls when it expands.
private void InitializeComboBox()
{
this.ComboBox1 = new System.Windows.Forms.ComboBox();
string[] employees = new string[]{"Hamilton, David", "Hensien, Kari",
"Hammond, Maria", "Harris, Keith", "Henshaw, Jeff D.",
"Hanson, Mark", "Harnpadoungsataya, Sariya",
"Harrington, Mark", "Harris, Keith", "Hartwig, Doris",
"Harui, Roger", "Hassall, Mark", "Hasselberg, Jonas",
"Harnpadoungsataya, Sariya", "Henshaw, Jeff D.",
"Henshaw, Jeff D.", "Hensien, Kari", "Harris, Keith",
"Henshaw, Jeff D.", "Hensien, Kari", "Hasselberg, Jonas",
"Harrington, Mark", "Hedlund, Magnus", "Hay, Jeff",
"Heidepriem, Brandon D."};
ComboBox1.Items.AddRange(employees);
this.ComboBox1.Location = new System.Drawing.Point(136, 32);
this.ComboBox1.IntegralHeight = false;
this.ComboBox1.MaxDropDownItems = 5;
this.ComboBox1.DropDownStyle = ComboBoxStyle.DropDownList;
this.ComboBox1.Name = "ComboBox1";
this.ComboBox1.Size = new System.Drawing.Size(136, 81);
this.ComboBox1.TabIndex = 0;
this.Controls.Add(this.ComboBox1);
// Associate the event-handling method with the
// SelectedIndexChanged event.
this.ComboBox1.SelectedIndexChanged +=
new System.EventHandler(ComboBox1_SelectedIndexChanged);
}
// This method is called when the user changes his or her selection.
// It searches for all occurrences of the selected employee's
// name in the Items array and adds the employee's name and
// the number of occurrences to TextBox1.Text.
// CAUTION This code exposes a known bug: If the index passed to the
// FindStringExact(searchString, index) method is the last index
// of the array, the code throws an exception.
private void ComboBox1_SelectedIndexChanged(object sender,
System.EventArgs e)
{
ComboBox comboBox = (ComboBox) sender;
// Save the selected employee's name, because we will remove
// the employee's name from the list.
string selectedEmployee = (string) ComboBox1.SelectedItem;
int count = 0;
int resultIndex = -1;
// Call the FindStringExact method to find the first
// occurrence in the list.
resultIndex = ComboBox1.FindStringExact(selectedEmployee);
// Remove the name as it is found, and increment the found count.
// Then call the FindStringExact method again, passing in the
// index of the current found item so the search starts there
// instead of at the beginning of the list.
while (resultIndex!=-1)
{
ComboBox1.Items.RemoveAt(resultIndex);
count += 1;
resultIndex = ComboBox1.FindStringExact(selectedEmployee,
resultIndex);
}
// Update the text in Textbox1.
TextBox1.Text = TextBox1.Text+ "\r\n" + selectedEmployee + ": "
+ count;
}
}
Imports System.Windows.Forms
Public Class Form1
Inherits System.Windows.Forms.Form
Public Sub New()
MyBase.New()
InitializeComboBox()
InitializeTextBox()
Me.Label1 = New System.Windows.Forms.Label
Me.SuspendLayout()
Me.Label1.Location = New System.Drawing.Point(8, 24)
Me.Label1.Name = "Label1"
Me.Label1.Size = New System.Drawing.Size(120, 32)
Me.Label1.TabIndex = 1
Me.Label1.Text = "Use drop-down to choose a name:"
Me.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleRight
Me.ClientSize = New System.Drawing.Size(292, 266)
Me.Controls.Add(Me.Label1)
Me.Name = "Form1"
Me.Text = "Form1"
Me.ResumeLayout(False)
End Sub
Shared Sub Main()
Application.Run(New Form1)
End Sub
Friend WithEvents Label1 As System.Windows.Forms.Label
' Declare and initialize the text box.
' This text box text will be update programmatically. The user is not
' allowed to update it, so the ReadOnly property is set to true.
Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
Private Sub InitializeTextBox()
Me.TextBox1 = New System.Windows.Forms.TextBox
Me.TextBox1.ScrollBars = ScrollBars.Vertical
Me.TextBox1.Location = New System.Drawing.Point(64, 128)
Me.TextBox1.Multiline = True
Me.TextBox1.Name = "TextBox1"
Me.TextBox1.ReadOnly = True
Me.TextBox1.Size = New System.Drawing.Size(184, 120)
Me.TextBox1.TabIndex = 4
Me.TextBox1.Text = "Employee and Number of Awards:"
Me.Controls.Add(Me.TextBox1)
End Sub
' Declare comboBox1 as a ComboBox.
Friend WithEvents ComboBox1 As System.Windows.Forms.ComboBox
' This method initializes the combo box, adding a large string
' array but limiting the drop-down size to six rows so the combo box
' doesn't cover other controls when it expands.
Private Sub InitializeComboBox()
Me.ComboBox1 = New System.Windows.Forms.ComboBox
Dim employees() As String = New String() {"Hamilton, David", _
"Hensien, Kari", "Hammond, Maria", "Harris, Keith", _
"Henshaw, Jeff D.", "Hanson, Mark", "Harnpadoungsataya, Sariya", _
"Harrington, Mark", "Harris, Keith", "Hartwig, Doris", _
"Harui, Roger", "Hassall, Mark", "Hasselberg, Jonas", _
"Harnpadoungsataya, Sariya", "Henshaw, Jeff D.", "Henshaw, Jeff D.", _
"Hensien, Kari", "Harris, Keith", "Henshaw, Jeff D.", _
"Hensien, Kari", "Hasselberg, Jonas", "Harrington, Mark", _
"Hedlund, Magnus", "Hay, Jeff", "Heidepriem, Brandon D."}
ComboBox1.Items.AddRange(employees)
Me.ComboBox1.Location = New System.Drawing.Point(136, 32)
Me.ComboBox1.IntegralHeight = False
Me.ComboBox1.MaxDropDownItems = 5
Me.ComboBox1.DropDownStyle = ComboBoxStyle.DropDown
Me.ComboBox1.Name = "ComboBox1"
Me.ComboBox1.Size = New System.Drawing.Size(136, 81)
Me.ComboBox1.TabIndex = 0
Me.Controls.Add(Me.ComboBox1)
End Sub
' This method is called when the user changes his or her selection.
' It searches for all occurrences of the selected employee's
' name in the Items array and adds the employee's name and
' the number of occurrences to TextBox1.Text.
' CAUTION This code exposes a known bug: If the index passed to the
' FindStringExact(searchString, index) method is the last index
' of the array, the code throws an exception.
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As Object, _
ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
Dim comboBox As comboBox = CType(sender, comboBox)
' Save the selected employee's name, because we will remove
' the employee's name from the list.
Dim selectedEmployee = CType(ComboBox1.SelectedItem, String)
Dim count As Integer = 0
Dim resultIndex As Integer = -1
' Call the FindStringExact method to find the first
' occurrence in the list.
resultIndex = ComboBox1.FindStringExact(ComboBox1.SelectedItem)
' Remove the name as it is found, and increment the found count.
' Then call the FindStringExact method again, passing in the index of the
' current found item so the search starts there instead of
' at the beginning of the list.
While (resultIndex <> -1)
ComboBox1.Items.RemoveAt(resultIndex)
count += 1
resultIndex = ComboBox1.FindStringExact _
(selectedEmployee, resultIndex)
End While
' Update the text in Textbox1.
TextBox1.Text = TextBox1.Text & Microsoft.VisualBasic.vbCrLf _
& selectedEmployee & ": " & count
End Sub
End Class
Comentarios
La búsqueda realizada por este método no distingue mayúsculas de minúsculas. El s parámetro es una cadena que se compara con el texto asociado a los elementos de la lista de cuadros combinados. La búsqueda busca una coincidencia a partir del principio del texto y devuelve el primer elemento de la lista que coincide con la subcadena especificada. A continuación, puede realizar tareas, como quitar el elemento que contiene el texto de búsqueda mediante el Remove método o cambiar el texto del elemento. Este método se usa normalmente después de realizar una llamada mediante la versión de este método que no especifica un índice inicial. Una vez que se ha encontrado un elemento inicial en la lista, este método se usa normalmente para buscar más instancias del texto de búsqueda especificando la posición de índice en el startIndex parámetro del elemento después de la primera instancia encontrada del texto de búsqueda. Si desea realizar una búsqueda parcial de palabras en lugar de una coincidencia exacta de palabras, use el FindString método .
La búsqueda realizada por este método es circular. Aunque la búsqueda se inicia en el siguiente índice después del startIndex parámetro , la búsqueda se reinicia a 0 cuando se alcanza el final de la colección. Sin embargo, tenga en cuenta que si el startIndex propio parámetro es igual al último índice de la colección, se produce una excepción.
Se aplica a
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