vb.net 如何从 ShowDialog 窗口返回一个值？
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How can I return a value from a ShowDialog window?
提问by Landmine
frmMain
主界面
DoSomething()
My.Forms.frmMessage.ShowDialog(Me)
If AcceptButtonClicked Then
' Do Code
DoCode()
Else
' Cancel Button Pressed
DoOtherCode()
End If
DoMore()
frmMessage
消息
My.Forms.frmMain.AcceptButtonClicked = True
Is there a way to pass a value from a Dialog window back to a paused thread on the main window? I want to know if they pressed the Ok or Cancel Button after filling out a form that pops up.
有没有办法将值从对话框窗口传递回主窗口上的暂停线程？我想知道他们在填写弹出的表格后是否按下了确定或取消按钮。
回答by Steve
You should set the AcceptButtonand the CancelButtonproperty on the Form, but also, the AcceptButtonshould have its property DialogResultset to OKand the CancelButtonto Cancel.
你应该设置AcceptButton和CancelButton财产的形式，而且，在AcceptButton应该有其属性DialogResult设置为OK和CancelButton以取消。
In this way, when your user presses one of these buttons the ShowDialog call returns and you can check the return value using the predefined values in the enum DialogResult
这样，当您的用户按下这些按钮之一时，ShowDialog 调用将返回，您可以使用枚举DialogResult 中的预定义值检查返回值
DoSomething()
Dim result = My.Forms.frmMessage.ShowDialog(Me)
If result = DialogResult.OK Then
' Do Code
DoCode()
Else
' Cancel Button Pressed
DoOtherCode()
End If
DoMore()
回答by Styxxy
You can use the DialogResultproperty on your form. This value will be returned by the ShowDialog function you call. You can also set this property on your buttonsso WinForms will handle the setting of the form property.
您可以DialogResult在表单上使用该属性。该值将由您调用的 ShowDialog 函数返回。您还可以在按钮上设置此属性，以便 WinForms 处理表单属性的设置。
In your frmMessageyou'll have to set the property accordingly (pick the one you need, OKand Cancel). Then you can check the return value easily:
在您中，frmMessage您必须相应地设置属性（选择您需要OKCancel的属性，和）。然后您可以轻松检查返回值：
If My.Forms.frmMessage.ShowDialog(Me) = System.Windows.Forms.DialogResult.OK Then
' OK button pressed
DoCode()
Else
' Cancel button pressed
DoOtherCode()
End If
Don't forget that the user might be able to close the form in another way than closing it with your buttons (e.g. by closing it with the close button).
不要忘记，用户可以用另一种方式关闭表单而不是用您的按钮关闭它（例如通过使用关闭按钮关闭它）。
回答by Wayne
The answers by Styxxyand Steveboth work for handling the DialogResultin the main window. However the DialogResultproperty for the Acceptbutton should not be set in the properties window, it should be set in your code after validationoccurs. This way if the user inputs bad data in the form they can get an error message and fix it without losing any work, instead of starting over.
Styxxy和Steve的答案都适用于处理DialogResult主窗口中的 。然而，按钮的DialogResult属性Accept不应在属性窗口中设置，而应在验证发生后在您的代码中设置。这样，如果用户在表单中输入错误数据，他们可以获得错误消息并修复它而不会丢失任何工作，而不是重新开始。
'code in Dialog Form
Private Sub btnAccept_Click(sender As System.Object, e As System.EventArgs) Handles btnAccept.Click
If IsValid() = True Then
DialogResult = Windows.Forms.DialogResult.OK
End If
End Sub
回答by aex
Me.DialogResult = Windows.Forms.DialogResult.Abort Me.Close()
Me.DialogResult = Windows.Forms.DialogResult.Abort Me.Close()
and it will return result Abort
它将返回结果中止
