DomainUpDown.DomainUpDownItemCollection.Add(Object) 方法

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

将指定的对象添加到集合末尾。

public:
 override int Add(System::Object ^ item);

public override int Add (object item);

public override int Add (object? item);

override this.Add : obj -> int

Public Overrides Function Add (item As Object) As Integer

参数

item

Object

要添加到集合末尾的 Object。

返回

Int32

添加到集合中的 Object 的从零开始的索引值。

示例

以下示例创建并初始化控件 DomainUpDown 。 该示例允许设置其某些属性，并创建字符串集合以在向上控件中显示。 代码假定已在窗体上实例化 a TextBoxCheckBox 和 aButton。 该示例还假定在类级别声明为名为 myCounter32 位有符号整数的成员变量。 可以在文本框中输入字符串，并在单击按钮时将其添加到 Items 集合。 通过单击复选框，可以切换 Sorted 属性并观察向上控件中项集合的差异。

protected:
   DomainUpDown^ domainUpDown1;

private:
   void InitializeMyDomainUpDown()
   {
      // Create and initialize the DomainUpDown control.
      domainUpDown1 = gcnew DomainUpDown;
      
      // Add the DomainUpDown control to the form.
      Controls->Add( domainUpDown1 );
   }

   void button1_Click( Object^ sender,
      EventArgs^ e )
   {
      // Add the text box contents and initial location in the collection
      // to the DomainUpDown control.
      domainUpDown1->Items->Add( String::Concat(
         (textBox1->Text->Trim()), " - ", myCounter ) );
      
      // Increment the counter variable.
      myCounter = myCounter + 1;
      
      // Clear the TextBox.
      textBox1->Text = "";
   }

   void checkBox1_Click( Object^ sender,
      EventArgs^ e )
   {
      
      // If Sorted is set to true, set it to false; 
      // otherwise set it to true.
      domainUpDown1->Sorted =  !domainUpDown1->Sorted;
   }

   void domainUpDown1_SelectedItemChanged( Object^ sender,
      EventArgs^ e )
   {
      
      // Display the SelectedIndex and 
      // SelectedItem property values in a MessageBox.
      MessageBox::Show( String::Concat( "SelectedIndex: ", domainUpDown1->SelectedIndex,
         "\nSelectedItem: ", domainUpDown1->SelectedItem ) );
   }

protected DomainUpDown domainUpDown1;

private void InitializeMyDomainUpDown()
 {
    // Create and initialize the DomainUpDown control.
    domainUpDown1 = new DomainUpDown();
    
    // Add the DomainUpDown control to the form.
    Controls.Add(domainUpDown1);
 }
 
 private void button1_Click(Object sender, 
                           EventArgs e)
 {   
    // Add the text box contents and initial location in the collection
    // to the DomainUpDown control.
    domainUpDown1.Items.Add((textBox1.Text.Trim()) + " - " + myCounter);
    
    // Increment the counter variable.
    myCounter = myCounter + 1;
 
    // Clear the TextBox.
    textBox1.Text = "";
 }
 
 private void checkBox1_Click(Object sender, 
                             EventArgs e)
 {
    // If Sorted is set to true, set it to false; 
    // otherwise set it to true.
    if (domainUpDown1.Sorted)
    {
       domainUpDown1.Sorted = false;
    }
    else
    {
       domainUpDown1.Sorted = true;
    }
 }
 
 private void domainUpDown1_SelectedItemChanged(Object sender, 
                                               EventArgs e)
 {
    // Display the SelectedIndex and 
    // SelectedItem property values in a MessageBox.
    MessageBox.Show("SelectedIndex: " + domainUpDown1.SelectedIndex.ToString() 
       + "\n" + "SelectedItem: " + domainUpDown1.SelectedItem.ToString());
 }

Protected domainUpDown1 As DomainUpDown


Private Sub InitializeMyDomainUpDown()
    ' Create and initialize the DomainUpDown control.
    domainUpDown1 = New DomainUpDown()
    
    ' Add the DomainUpDown control to the form.
    Controls.Add(domainUpDown1)
End Sub


Private Sub button1_Click(sender As Object, e As EventArgs)
    ' Add the text box contents and initial location in the collection
    ' to the DomainUpDown control.
    domainUpDown1.Items.Add((textBox1.Text.Trim() & " - " & myCounter))
    
    ' Increment the counter variable.
    myCounter = myCounter + 1
    
    ' Clear the TextBox.
    textBox1.Text = ""
End Sub


Private Sub checkBox1_Click(sender As Object, e As EventArgs)
    ' If Sorted is set to true, set it to false; 
    ' otherwise set it to true.
    If domainUpDown1.Sorted Then
        domainUpDown1.Sorted = False
    Else
        domainUpDown1.Sorted = True
    End If
End Sub


Private Sub domainUpDown1_SelectedItemChanged _
    (sender As Object, e As EventArgs)
    
    ' Display the SelectedIndex and 
    ' SelectedItem property values in a MessageBox.
    MessageBox.Show(("SelectedIndex: " & domainUpDown1.SelectedIndex.ToString() & _
        ControlChars.Cr & "SelectedItem: " & domainUpDown1.SelectedItem.ToString()))
End Sub

注解

还可以使用Insert该方法向集合添加新Object项。

若要删除之前添加的项 Object ，请使用 Remove 或 RemoveAt 方法。

另请参阅

• Insert(Int32, Object)
• Remove(Object)
• RemoveAt(Int32)