UpDownBase.Select(Int32, Int32) 方法

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

指定要選取的開始位置和字元數目，以在微調方塊 (也稱為上下按鈕控制項) 中選取文字的範圍。

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)

參數

start

Int32

要選取的第一個字元的位置。

length

Int32

要選取的字元總數。

範例

下列程式碼範例使用衍生類別 NumericUpDown 。 此程式碼需要 NumericUpDown 已在表單上建立控制項和 ， Button 且 System.Drawing 命名空間已新增為參考。 Click在按鈕的事件上，控制項中的 NumericUpDown 文字點大小會增加。 這會提示控制項調整其 PreferredHeight 屬性，讓控制項中可以看到所有文字。 當使用者輸入新的值並離開 NumericUpDown 控制項之後，文字會從字串值轉換成數值，並驗證為 介於 和 Maximum 值之間 Minimum 。 如果值無效， MessageBox 則會以錯誤顯示 ，而 Select 方法會選取文字，讓使用者可以輸入新的值。

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

備註

當 Select 微調方塊取得焦點，或屬性失敗資料驗證時 Text ，可以使用 方法。 在衍生類別中新增 ValidateEditText 方法的驗證碼時，請在驗證失敗時呼叫 Select 方法。

另請參閱

• ValidateEditText()