如何将ByRef变量持久化到.net winforms对话框窗体中?

在这种情况下,我通常

• 编写一个ShowDialog函数,该函数执行我想要的操作(例如返回值)或
• 让结果成为对话框中的一个属性。这是常见文件对话框在BCL中的操作方式。然后调用方必须读取该属性才能获得结果。我认为那很好。

例如,我会将此添加为使用说明(对不起,这里没有VB,您说C#是受欢迎的):

using (var dlg = new DeptPicker()) {
    if (dlg.ShowDialog() == DialogResult.OK) {
        myTextBoxOrWhatEver.Text = dlg.TargetResult;
    }
}

void okButton_Click(object sender, EventArgs e)
{
    TargetResult = whatever; // can also do this when the selection changes
    DialogResult = DialogResult.OK;
    Close();
}

不过,我在这个示例中没有使用新的ShowDialog实现。

至于如何制作指向原作的“指针”,我不知道。

由于VB.NET不支持不安全的代码块,因此无法对字符串进行指针引用,这使得这一点更加困难。

让用户选择任何部门。当用户单击“确定”时,将引用文本框的文本属性设置为所选部门的文本或id(取决于您的需要)

我正在使用您提供的代码。

Public Class DeptPicker

   Private m_TargetTextBox As TextBox

   Public Sub New(ByRef TargetTextBox As TextBox)
      InitializeComponent()

      m_TargetTextBox = TargetTextBox

   End Sub

   Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click

      DialogResult = Windows.Forms.DialogResult.OK

      ' I get no love here. m_TargetResult is just a string and doesn't push the value back to the referenced variable I want.
      m_TargetTextBox.Text = "That department I selected."
      Me.Close()

   End Sub

   Private Sub btnCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click

      DialogResult = Windows.Forms.DialogResult.Cancel
      Me.Close()

   End Sub

End Class

Public Class DeptPicker

    dim dlgResult as DialogResult

    Public Function GetSelectedDepartment() As String
        Me.Show vbModal
        If (dlgResult = Windows.Forms.DialogResult.OK) Then
            return "selected department string here"
        Else
            return "sorry, you didnt canceled on the form"
        End If
    End Function

    Private Sub btnOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOK.Click
        dlgResult = Windows.Forms.DialogResult.OK
        Me.Close()
    End Sub

    Private Sub btnCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click
        dlgResult = Windows.Forms.DialogResult.Cancel
        Me.Close()
    End Sub
End Class

主持人:这个看起来更好吗?

用户可以调用new DeptPicker().GetSelectedDepartment()。

谢谢主持人。现在,它看起来还好吗?

这可能会起作用:

    // This code in your dialog form.  Hide the base showdialog method 
    // and implement your own versions
    public new string ShowDialog() {
        return this.ShowDialog(null);
    }

    public new string ShowDialog(IWin32Window owner) {
        // Call the base implementation of show dialog
        base.ShowDialog(owner);

        // You get here after the close button is clicked and the form is hidden.  Capture the data you want.
        string s = this.someControl.Text;

        // Now really close the form and return the value
        this.Close();
        return s;
    }

    // On close, just hide.  Close in the show dialog method
    private void closeButton_Click(object sender, EventArgs e) {
        this.Hide();
    }

    // This code in your calling form
    MyCustomForm f = new MyCustomForm();
    string myAnswer = f.ShowDialog();