使用MessageBox清除文本框是按鈕

Question

我想出瞭如何清除文本框，但是當我在MessageBox上按否時清除了該文本框。我想清除用戶是否選擇是。如果用戶選擇否那麼我想什麼都不做。

Private Sub BtnFah_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnFah.Click 
     Try 
      Dim intFah As Integer 
      intFah = CInt(TxtBoxTemp.Text) 
      intFah = (intFah * 9)/5 - 32 
      If MessageBox.Show(intFah.ToString & ControlChars.CrLf & "Would you like to start another temp conversion?", "Result", MessageBoxButtons.YesNo) Then 
       TxtBoxTemp.Text = String.Empty 
      End If 
     Catch 
      MessageBox.Show("Would you like to start another temp conversion?", "System Error", MessageBoxButtons.YesNo) 

     End Try 
    End Sub 

Answer 1

您需要比較DialogResult

Public Class Form1  
    Private Sub BtnFah_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnFah.Click 
     Try 
      Dim intFah As Integer 
      intFah = CInt(TxtBoxTemp.Text) 
      intFah = (intFah * 9)/5 - 32 
      If MessageBox.Show(intFah.ToString & ControlChars.CrLf & "Would you like to start another temp conversion?", "Result", MessageBoxButtons.YesNo) = DialogResult.Yes Then 
       TxtBoxTemp.Text = String.Empty 
      End If 
     Catch 
      MessageBox.Show("Would you like to start another temp conversion?", "System Error", MessageBoxButtons.YesNo) 

     End Try 
    End Sub 
End Class 

Answer 2

MessageBox.Show返回DialogResult。你應該爲DialogResult.Yes檢查：

If MessageBox.Show(...) = DialogResult.Yes Then 
    TxtBoxTemp.Text = String.Empty 
End If 

Answer 3

運用Q作爲變量，暗淡的msgboxresult來取得了MSGBOX有結果，如果按是，文本框將會清楚，如果不是，那麼它將返回或什麼都不做

Dim q As MsgBoxResult 
      q = MsgBox("Your Question", vbYesNo) 
      If q = vbYes Then 
       TextBox1.Clear() 
      Else 
       Return 
      End If 

Answer 4

嘗試......

If MessageBox.Show("Your Message", "Title", MessageBoxButtons.YesNo) = DialogResult.Yes Then 
textbox.clear() 
End If