DomainUpDown.SelectedIndex 属性

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

获取或设置选定项的索引值。

public:
 property int SelectedIndex { int get(); void set(int value); };

[System.ComponentModel.Browsable(false)]
public int SelectedIndex { get; set; }

[<System.ComponentModel.Browsable(false)>]
member this.SelectedIndex : int with get, set

Public Property SelectedIndex As Integer

属性值

Int32

选定项的从零开始的索引值。 默认值为 -1。

属性

BrowsableAttribute

例外

ArgumentOutOfRangeException

分配的值小于默认值 -1。

- 或 -

分配的值大于 Items 数。

示例

下面的代码示例创建并初始化 控件 DomainUpDown 。 该示例允许您设置其某些属性，并创建字符串集合以在旋转框中显示。 该代码假定 TextBox、 CheckBox和 Button 已在窗体上实例化。 该示例还假定你在类级别有一个声明为名为 myCounter的 32 位带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 Items 添加到集合中。 通过单击该复选框，可以切换 Sorted 属性并观察自旋框中项集合的差异。

protected:
   DomainUpDown^ domainUpDown1;

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

   void button1_Click( System::Object^ sender,
     System::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.ToString() ) );
      
      // 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.
      if ( domainUpDown1->Sorted )
      {
         domainUpDown1->Sorted = false;
      }
      else
      {
         domainUpDown1->Sorted = true;
      }
   }

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

protected DomainUpDown domainUpDown1;

private void MySub()
 {
    // Create and initialize the DomainUpDown control.
    domainUpDown1 = new System.Windows.Forms.DomainUpDown();
    
    // Add the DomainUpDown control to the form.
    Controls.Add(domainUpDown1);
 }
 
 private void button1_Click(System.Object sender, 
                           System.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(System.Object sender, 
                             System.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(System.Object sender, 
                                               System.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 MySub()
    ' Create and initialize the DomainUpDown control.
    domainUpDown1 = New System.Windows.Forms.DomainUpDown()
    
    ' Add the DomainUpDown control to the form.
    Controls.Add(domainUpDown1)
End Sub


Private Sub button1_Click(sender As System.Object, e As System.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 System.Object, e As System.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 System.Object, e As System.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

属性 SelectedIndex 保存集合中当前在旋转框中选择的项的索引值， (也称为向上向下控件) 。 如果 Sorted 属性已从 falsetrue更改为 ，则可以为集合项重新分配新的索引值。 当集合按字母顺序重新排序时，将为这些项分配一个新的索引值。

注意

如果用户在旋转框中输入了项，或者未选择任何项，则 SelectedIndex 该值将为默认值 -1。

另请参阅

• SelectedItem