内容が境界を超えているときにテキストボックス内にスクロールバーを表示するC＃

Question

テキストボックス内の行数が表示される行数を超えている場合にのみスクロールバーをテキストボックスに表示/非表示できますか？

Answer 1

はRichTextBoxを使用することを検討してください - それは内蔵のその行動を持って

Answer 2

Public Class TextBoxScrollbarPlugin 
    Private WithEvents mTarget As TextBox 

    ''' <summary> 
    ''' After the Handle is created, mTarget.IsHandleCreated always returns 
    ''' TRUE, even after HandleDestroyed is fired. 
    ''' </summary> 
    ''' <remarks></remarks> 
    Private mIsHandleCreated As Boolean = False 

    Public Sub New(item As TextBox) 
     mTarget = item 
     mIsHandleCreated = mTarget.IsHandleCreated 
    End Sub 

    Private Sub Update() 
     If Not mTarget.IsHandleCreated Then 
      Return 
     ElseIf Not mIsHandleCreated Then 
      Return 
     End If 
     Dim textBoxRect = TextRenderer.MeasureText(mTarget.Text, 
                mTarget.Font, 
                New Size(mTarget.Width, Integer.MaxValue), 
                TextFormatFlags.WordBreak + TextFormatFlags.TextBoxControl) 

     Try 
      If textBoxRect.Height > mTarget.Height Then 
       mTarget.ScrollBars = ScrollBars.Vertical 
      Else 
       mTarget.ScrollBars = ScrollBars.None 
      End If 
     Catch ex As System.ComponentModel.Win32Exception 
      'this sometimes throws a "failure to create window handle" 
      'error. 
      'This might happen if the TextBox is unvisible and/or 
      'to small to display a toolbar. 
      If mLog.IsWarnEnabled Then mLog.Warn("Update()", ex) 
     End Try 
    End Sub 

    Private Sub mTarget_HandleCreated(sender As Object, e As System.EventArgs) Handles mTarget.HandleCreated 
     mIsHandleCreated = True 
    End Sub 

    Private Sub mTarget_HandleDestroyed(sender As Object, e As System.EventArgs) Handles mTarget.HandleDestroyed 
     mIsHandleCreated = False 
    End Sub 

    Private Sub mTarget_SizeChanged(sender As Object, e As System.EventArgs) Handles mTarget.SizeChanged 
     Update() 
    End Sub 

    Private Sub mTarget_TextChanged(sender As Object, e As System.EventArgs) Handles mTarget.TextChanged 
     Update() 
    End Sub 

End Class 


Private mPlugins As New List(Of Object) 
Private Sub Form_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 
    mPlugins.Add(New TextBoxScrollbarPlugin(txtBoxOne)) 
    mPlugins.Add(New TextBoxScrollbarPlugin(txtBoxTwo)) 
    mPlugins.Add(New TextBoxScrollbarPlugin(txtBoxThree)) 
End Sub 

Answer 3

おかげダミー、それが動作します。！ここでは、C＃でダミーの答えの短いバージョンあなたSizeChangedの終わりに

コールこのコードをしてハンドラをTextChanged：

Size textBoxRect = TextRenderer.MeasureText(
    this.YourTextBox.Text, 
    this.YourTextBox.Font, 
    new Size(this.YourTextBox.Width, int.MaxValue), 
    TextFormatFlags.WordBreak | TextFormatFlags.TextBoxControl); 
try 
{ 
    this.YourTextBox.ScrollBars = textBoxRect.Height > this.YourTextBox.Height ? 
     ScrollBars.Vertical : 
     ScrollBars.None; 
} catch (System.ComponentModel.Win32Exception) 
{ 
    // this sometimes throws a "failure to create window handle" error. 
    // This might happen if the TextBox is unvisible and/or 
    // too small to display a toolbar. 
} 

Answer 4

私はVBで働いtnimasソリューションを持っています。書かれたように機能し、エラーは見られませんでした。

Private Sub TextBoxSizeChanged(sender As Object, e As EventArgs) Handles Me.SizeChanged 
    Dim textBoxRect As Size = TextRenderer.MeasureText(TextBox.Text, TextBox.Font, New Size(TextBox.Width, Integer.MaxValue), TextFormatFlags.WordBreak Or TextFormatFlags.TextBoxControl) 
    Try 
     TextBox.ScrollBar = If(textBoxRect.Height > TextBox.Height, ScrollBars.Vertical, ScrollBars.None) 
    Catch ex As Exception 
     'handle error 
    End Try 
End Sub