通过

UpDownBase.Select(Int32, Int32) 方法

定义

命名空间:
System.Windows.Forms
程序集:
System.Windows.Forms.dll
Source:
UpDownBase.cs
Source:
UpDownBase.cs
Source:
UpDownBase.cs
Source:
UpDownBase.cs
Source:
UpDownBase.cs

在旋转框中（也称为向上控件）中选择一系列文本，指定要选择的起始位置和字符数。

public:
 void Select(int start, int length);
public void Select(int start, int length);
override this.Select : int * int -> unit
Public Sub Select (start As Integer, length As Integer)

参数

start
Int32

要选择的第一个字符的位置。

length
Int32

要选择的字符总数。

示例

下面的代码示例使用派生类 NumericUpDown。 此代码要求 NumericUpDown 在窗体上创建控件和 a， Button 并且 System.Drawing 命名空间已添加为引用。 在按钮的事件中 Click ，控件中 NumericUpDown 文本的点大小会增加。 这会提示控件调整其 PreferredHeight 属性，以便控件中的所有文本在控件中可见。 用户输入新值并离开NumericUpDown控件后，文本将从字符串值转换为数值，并验证为介于值和Maximum值之间Minimum。 如果值无效，则会显示错误， MessageBox 并且 Select 该方法将选择文本，以便用户可以输入新值。

void numericUpDown1_Leave( Object^ /*sender*/, EventArgs^ /*e*/ )
{
   /* If the entered value is greater than Minimum or Maximum,
         select the text and open a message box. */
   if ( (System::Convert::ToInt32( numericUpDown1->Text ) > numericUpDown1->Maximum) || (System::Convert::ToInt32( numericUpDown1->Text ) < numericUpDown1->Minimum) )
   {
      MessageBox::Show( "The value entered was not between the Minimum andMaximum allowable values.\nPlease re-enter." );
      numericUpDown1->Focus();
      numericUpDown1->Select(0,numericUpDown1->Text->Length);
   }
}

void button1_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
{
   int varPrefHeight1;
   
   /* Capture the PreferredHeight before and after the Font
         is changed, and display the results in a message box. */
   varPrefHeight1 = numericUpDown1->PreferredHeight;
   numericUpDown1->Font = gcnew System::Drawing::Font( "Microsoft Sans Serif",12.0,System::Drawing::FontStyle::Bold );
   MessageBox::Show( String::Format( "Before Font Change: {0}\nAfter Font Change: {1}", varPrefHeight1, numericUpDown1->PreferredHeight ) );
}

private void numericUpDown1_Leave(Object sender,
                                  EventArgs e)
{
   /* If the entered value is greater than Minimum or Maximum,
      select the text and open a message box. */
   if((System.Convert.ToInt32(numericUpDown1.Text) > numericUpDown1.Maximum) ||
      (System.Convert.ToInt32(numericUpDown1.Text) < numericUpDown1.Minimum))
   {
      MessageBox.Show("The value entered was not between the Minimum and" +
         "Maximum allowable values." + "\n" + "Please re-enter.");
      numericUpDown1.Focus();
      numericUpDown1.Select(0, numericUpDown1.Text.Length);
   }
}
   
private void button1_Click(Object sender,
                           EventArgs e)
{
   int varPrefHeight1;
   
   /* Capture the PreferredHeight before and after the Font
      is changed, and display the results in a message box. */
   varPrefHeight1 = numericUpDown1.PreferredHeight;
   numericUpDown1.Font = new System.Drawing.Font("Microsoft Sans Serif",
      12F, System.Drawing.FontStyle.Bold);
   MessageBox.Show("Before Font Change: " + varPrefHeight1.ToString() +
      "\n" + "After Font Change: " + numericUpDown1.PreferredHeight.ToString());
}

Private Sub numericUpDown1_Leave(sender As Object, e As EventArgs)
    ' If the entered value is greater than Minimum or Maximum,
    ' select the text and open a message box. 
    If (System.Convert.ToInt32(numericUpDown1.Text) > numericUpDown1.Maximum) Or _
        (System.Convert.ToInt32(numericUpDown1.Text) < numericUpDown1.Minimum) Then
        MessageBox.Show("The value entered was not between the Minimum and " & _
            "Maximum allowable values." & Microsoft.VisualBasic.ControlChars.Cr & _
            "Please re-enter.")
        numericUpDown1.Focus()
        numericUpDown1.Select(0, numericUpDown1.Text.Length)
    End If
End Sub    

Private Sub button1_Click(sender As Object, e As EventArgs)
    Dim varPrefHeight1 As Integer
    
    ' Capture the PreferredHeight before and after the Font
    ' is changed, and display the results in a message box. 
    varPrefHeight1 = numericUpDown1.PreferredHeight
    numericUpDown1.Font = New System.Drawing.Font("Microsoft Sans Serif", _
        12F, System.Drawing.FontStyle.Bold)
    MessageBox.Show("Before Font Change: " & varPrefHeight1.ToString() & _
        Microsoft.VisualBasic.ControlChars.Cr & "After Font Change: " & _
        numericUpDown1.PreferredHeight.ToString())
End Sub

注解

当 Select 旋转框获得焦点或属性未能通过数据验证时 Text ，可以使用该方法。 在派生类中添加方法的 ValidateEditText 验证代码时，在验证失败时调用该方法 Select 。

适用于

另请参阅