UpDownBase.Select(Int32, Int32) 方法

定義

命名空間:

System.Windows.Forms

組件:

System.Windows.Forms.dll

來源:

UpDownBase.cs

在旋轉框（也稱為上下控制）中選取一系列文字，指定起始位置及可選擇字元數。

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

第一個被選中角色的位置。

length

Int32

要選中的總角色數。

範例

以下程式碼範例使用導出類別 NumericUpDown。 此程式碼要求 NumericUpDown 在表單上建立控制項與 a Button ，且 System.Drawing 新增命名空間作為參考。 在按鈕事件中 Click ，控制點的文字 NumericUpDown 大小會增加。 這會促使控制項調整屬性 PreferredHeight ，使所有文字都能在控制項中顯示。 使用者輸入新值並離開NumericUpDown控制項後，文字會從字串值轉換成數字值，並驗證其位於 和 Maximum 值之間Minimum。 若值不正確，會顯示 a MessageBox 並顯示錯誤， Select 方法會選擇該文字，讓使用者輸入新值。

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

備註

Select當自旋盒被聚焦，或Text屬性在資料驗證失敗時，可使用此方法。 在為衍生類別新增方法驗證程式碼 ValidateEditText 時，驗證失敗時呼叫該 Select 方法。

另請參閱

• ValidateEditText()