ListControl.DataSource 属性
获取或设置此 ListControl 的数据源。
**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms(在 system.windows.forms.dll 中)
语法
声明
Public Property DataSource As Object
用法
Dim instance As ListControl
Dim value As Object
value = instance.DataSource
instance.DataSource = value
public Object DataSource { get; set; }
public:
property Object^ DataSource {
Object^ get ();
void set (Object^ value);
}
/** @property */
public Object get_DataSource ()
/** @property */
public void set_DataSource (Object value)
public function get DataSource () : Object
public function set DataSource (value : Object)
属性值
实现 IList 或 IListSource 接口的对象,如 DataSet 或 Array。默认为 空引用(在 Visual Basic 中为 Nothing)。
异常
异常类型 | 条件 |
---|---|
指定的值未实现 IList 或 IListSource 接口。 |
备注
有两种方式可以填充 ComboBox 和 ListBox 控件。
例如,使用 Add 方法可向 ComboBox 中添加对象。也可以通过用 DataSource、DisplayMember 和 ValueMember 属性填充 ComboBox 来向 ComboBox 添加对象。
设置了 DataSource 属性之后,用户不能修改项集合。
如果设置 DataSource 属性导致数据源更改,则将引发 DataSourceChanged 事件。如果设置此属性导致数据成员更改,则将引发 DisplayMemberChanged 事件。
将 DataSource 设置成 空引用(在 Visual Basic 中为 Nothing) 时,DisplayMember 将设置为空字符串 ("")。
示例
下面的代码示例是一个完整的应用程序,它说明在 ListBox 类实现了 ListControl 类的 DataSource、DisplayMember、ValueMember 和 SelectedValue 等成员后,如何使用这些成员。本示例加载了 ArrayList 和列表框。当用户在列表框中选择了一个项时,将把选定的值用于返回与选定的项关联的数据。
Imports System
Imports System.Windows.Forms
Imports System.Drawing
Imports System.Collections
Public Class USState
Private myShortName As String
Private myLongName As String
Public Sub New(strLongName As String, strShortName As String)
Me.myShortName = strShortName
Me.myLongName = strLongName
End Sub 'New
Public ReadOnly Property ShortName() As String
Get
Return myShortName
End Get
End Property
Public ReadOnly Property LongName() As String
Get
Return myLongName
End Get
End Property
Public Overrides Function ToString() As String
Return Me.ShortName + " - " + Me.LongName
End Function 'ToString
End Class 'USState
Public Class ListBoxSample3
Inherits Form
Private ListBox1 As New ListBox()
Private textBox1 As New TextBox()
<STAThread()> _
Shared Sub Main()
Application.Run(New ListBoxSample3())
End Sub 'Main
Public Sub New()
Me.ClientSize = New Size(292, 181)
Me.Text = "ListBox Sample3"
ListBox1.Location = New Point(24, 16)
ListBox1.Name = "ListBox1"
ListBox1.Size = New Size(232, 130)
textBox1.Location = New Point(24, 160)
textBox1.Name = "textBox1"
textBox1.Size = New Size(240, 24)
Me.Controls.AddRange(New Control() {ListBox1, textBox1})
' Populates the list box using DataSource.
' DisplayMember is used to display just the long name of each state.
Dim USStates As New ArrayList()
USStates.Add(New USState("Alabama", "AL"))
USStates.Add(New USState("Washington", "WA"))
USStates.Add(New USState("West Virginia", "WV"))
USStates.Add(New USState("Wisconsin", "WI"))
USStates.Add(New USState("Wyoming", "WY"))
AddHandler ListBox1.SelectedValueChanged, AddressOf ListBox1_SelectedValueChanged
ListBox1.DataSource = USStates
ListBox1.DisplayMember = "LongName"
ListBox1.ValueMember = "ShortName"
End Sub 'New
Private Sub InitializeComponent()
End Sub 'InitializeComponent
Private Sub ListBox1_SelectedValueChanged(sender As Object, e As EventArgs)
If ListBox1.SelectedIndex <> - 1 Then
textBox1.Text = ListBox1.SelectedValue.ToString()
End If
End Sub 'ListBox1_SelectedValueChanged
End Class 'ListBoxSample3
using System;
using System.Windows.Forms ;
using System.Drawing ;
using System.Collections ;
namespace MyListControlSample
{
public class USState
{
private string myShortName ;
private string myLongName ;
public USState(string strLongName, string strShortName)
{
this.myShortName = strShortName;
this.myLongName = strLongName;
}
public string ShortName
{
get
{
return myShortName;
}
}
public string LongName
{
get
{
return myLongName ;
}
}
public override string ToString()
{
return this.ShortName + " - " + this.LongName;
}
}
public class ListBoxSample3:Form
{
private ListBox ListBox1 = new ListBox();
private TextBox textBox1 = new TextBox() ;
[STAThread]
static void Main()
{
Application.Run(new ListBoxSample3()) ;
}
public ListBoxSample3()
{
this.ClientSize = new Size(292, 181) ;
this.Text = "ListBox Sample3" ;
ListBox1.Location = new Point(24, 16) ;
ListBox1.Name = "ListBox1" ;
ListBox1.Size = new Size(232, 130) ;
textBox1.Location = new Point(24, 160) ;
textBox1.Name = "textBox1" ;
textBox1.Size = new Size(240, 24) ;
this.Controls.AddRange(new Control[] {ListBox1, textBox1}) ;
// Populates the list box using DataSource.
// DisplayMember is used to display just the long name of each state.
ArrayList USStates = new ArrayList() ;
USStates.Add(new USState("Alabama", "AL"));
USStates.Add(new USState("Washington", "WA")) ;
USStates.Add(new USState("West Virginia", "WV"));
USStates.Add(new USState("Wisconsin", "WI")) ;
USStates.Add(new USState("Wyoming", "WY"));
ListBox1.SelectedValueChanged += new EventHandler(ListBox1_SelectedValueChanged);
ListBox1.DataSource = USStates ;
ListBox1.DisplayMember = "LongName" ;
ListBox1.ValueMember = "ShortName" ;
}
private void InitializeComponent()
{
}
private void ListBox1_SelectedValueChanged(object sender, EventArgs e)
{
if (ListBox1.SelectedIndex != -1)
textBox1.Text = ListBox1.SelectedValue.ToString();
}
}
}
#using <System.dll>
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>
using namespace System;
using namespace System::Windows::Forms;
using namespace System::Drawing;
using namespace System::Collections;
public ref class USState
{
private:
String^ myShortName;
String^ myLongName;
public:
USState( String^ strLongName, String^ strShortName )
{
this->myShortName = strShortName;
this->myLongName = strLongName;
}
property String^ ShortName
{
String^ get()
{
return myShortName;
}
}
property String^ LongName
{
String^ get()
{
return myLongName;
}
}
virtual String^ ToString() override
{
return String::Concat( this->ShortName, " - ", this->LongName );
}
};
public ref class ListBoxSample3: public Form
{
private:
ListBox^ ListBox1;
TextBox^ textBox1;
public:
ListBoxSample3()
{
ListBox1 = gcnew ListBox;
textBox1 = gcnew TextBox;
this->ClientSize = System::Drawing::Size( 292, 181 );
this->Text = "ListBox Sample3";
ListBox1->Location = Point(24,16);
ListBox1->Name = "ListBox1";
ListBox1->Size = System::Drawing::Size( 232, 130 );
textBox1->Location = Point(24,160);
textBox1->Name = "textBox1";
textBox1->Size = System::Drawing::Size( 240, 24 );
array<Control^>^temp2 = {ListBox1,textBox1};
this->Controls->AddRange( temp2 );
// Populates the list box using DataSource.
// DisplayMember is used to display just the long name of each state.
ArrayList^ USStates = gcnew ArrayList;
USStates->Add( gcnew USState( "Alabama","AL" ) );
USStates->Add( gcnew USState( "Washington","WA" ) );
USStates->Add( gcnew USState( "West Virginia","WV" ) );
USStates->Add( gcnew USState( "Wisconsin","WI" ) );
USStates->Add( gcnew USState( "Wyoming","WY" ) );
ListBox1->SelectedValueChanged += gcnew EventHandler( this, &ListBoxSample3::ListBox1_SelectedValueChanged );
ListBox1->DataSource = USStates;
ListBox1->DisplayMember = "LongName";
ListBox1->ValueMember = "ShortName";
}
void InitializeComponent(){}
private:
void ListBox1_SelectedValueChanged( Object^ /*sender*/, EventArgs^ /*e*/ )
{
if ( ListBox1->SelectedIndex != -1 )
textBox1->Text = ListBox1->SelectedValue->ToString();
}
};
[STAThread]
int main()
{
Application::Run( gcnew ListBoxSample3 );
}
package MyListControlSample;
import System.*;
import System.Windows.Forms.*;
import System.Drawing.*;
import System.Collections.*;
public class USState
{
private String myShortName;
private String myLongName;
public USState(String strLongName, String strShortName)
{
this.myShortName = strShortName;
this.myLongName = strLongName;
} //USState
/** @property
*/
public String get_ShortName()
{
return myShortName;
}//get_ShortName
/** @property
*/
public String get_LongName()
{
return myLongName;
}//get_LongName
public String ToString()
{
return this.get_ShortName() + " - " + this.get_LongName();
} //ToString
} //USState
public class ListBoxSample3 extends Form
{
private ListBox listBox1 = new ListBox();
private TextBox textBox1 = new TextBox();
/** @attribute STAThread()
*/
public static void main(String[] args)
{
Application.Run(new ListBoxSample3());
} //main
public ListBoxSample3()
{
this.set_ClientSize(new Size(292, 181));
this.set_Text("ListBox Sample3");
listBox1.set_Location(new Point(24, 16));
listBox1.set_Name("ListBox1");
listBox1.set_Size(new Size(232, 130));
textBox1.set_Location(new Point(24, 160));
textBox1.set_Name("textBox1");
textBox1.set_Size(new Size(240, 24));
this.get_Controls().AddRange(new Control[] { listBox1, textBox1 });
// Populates the list box using DataSource.
// DisplayMember is used to display just the long name of each state.
ArrayList uSStates = new ArrayList();
uSStates.Add(new USState("Alabama", "AL"));
uSStates.Add(new USState("Washington", "WA"));
uSStates.Add(new USState("West Virginia", "WV"));
uSStates.Add(new USState("Wisconsin", "WI"));
uSStates.Add(new USState("Wyoming", "WY"));
listBox1.add_SelectedValueChanged(
new EventHandler(listBox1_SelectedValueChanged));
listBox1.set_DataSource(uSStates);
listBox1.set_DisplayMember("LongName");
listBox1.set_ValueMember("ShortName");
} //ListBoxSample3
private void InitializeComponent()
{
} //InitializeComponent
private void listBox1_SelectedValueChanged(Object sender, EventArgs e)
{
if (listBox1.get_SelectedIndex() != -1) {
textBox1.set_Text(listBox1.get_SelectedValue().ToString());
}
} //listBox1_SelectedValueChanged
} //ListBoxSample3
平台
Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表,请参见系统要求。
版本信息
.NET Framework
受以下版本支持:2.0、1.1、1.0
.NET Compact Framework
受以下版本支持:2.0、1.0