[英]How allows ShowDialog MDI children on MDI Form parent?
In the MDI Parent Forms (With the property this.IsMdiContainer = true
) we don't are allowed to display any children forms with the method ShowDialog()
; 在MDI父表单(具有属性
this.IsMdiContainer = true
)中,我们不允许使用ShowDialog()
方法显示任何子表单; automatically will throw the following exception: 自动将引发以下异常:
A first chance exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll
类型“ System.InvalidOperationException”的第一次机会异常发生在System.Windows.Forms.dll中
Additional information: Form that is not a top-level form cannot be displayed as a modal dialog box.
附加信息:不是顶级表单的表单不能显示为模式对话框。 Remove the form from any parent form before calling showDialog.
在调用showDialog之前,从任何父表单中删除该表单。
Did anyone has figured out a workaround this problem? 有谁找到解决此问题的方法?
An easy and clean solution that I implemented on my projects is using a callback function ( Action<T>
in C#) that is triggered when the user put the wanted input. 我在项目上实现的一种简单干净的解决方案是使用回调函数(在C#中为
Action<T>
),该回调函数在用户放置所需的输入时触发。
Example using ShowDialog: 使用ShowDialog的示例:
private void cmdGetList_Click(object sender, EventArgs e)
{
string strInput = "";
frmInputBox frmDialog = new frmInputBox("User input:");
if (frmDialog.ShowDialog() == DialogResult.OK)
strInput = frmDialog.prpResult;
else
strInput = null;
}
The input box it's outside the MDI Main Form.
输入框在MDI Main Form之外。
Now; 现在; the solution using Show:
使用Show解决方案:
private void cmdGetList_Click(object sender, EventArgs e)
{
getInput(this, (string strResult) =>
{
MessageBox.Show(strResult);
});
}
private void getInput(Form frmParent, Action<string> callback)
{
// CUSTOM INPUT BOX
frmInputBox frmDialog = new frmInputBox("User input:");
// EVENT TO DISPOSE THE FORM
frmDialog.FormClosed += (object closeSender, FormClosedEventArgs closeE) =>
{
frmDialog.Dispose();
frmDialog = null;
};
frmDialog.MdiParent = frmParent; // Previosuly I set => frmParent.IsMdiContainer = true;
// frmDialog.ShowDialog(); <== WILL RAISE AN ERROR
// INSTEAD OF:
frmDialog.MdiParent = frmParent;
frmDialog.FormClosing += (object sender, FormClosingEventArgs e) =>
{
if (frmDialog.DialogResult == DialogResult.OK)
callback(frmDialog.prpResult);
else
callback(null);
};
frmDialog.Show();
}
The input box (Or any form will display inside the MDI parent form): 输入框(或任何表单将显示在MDI父表单内):
The trick is to use a callback function (Action on C#) to manage when the user put an input. 诀窍是使用回调函数(对C#进行操作)来管理用户输入内容的时间。
It's more code lines, but it's worthless to display a clean project. 这是更多的代码行,但是显示干净的项目毫无价值。
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