在关闭usercontrol之前提示保存值的问题 [英] Problem with prompting save values before usercontrol be closed

问题描述

我有一个名为test的用户控件

I have a user control named "test"

public partial class test : UserControl
{
    string clean;
    public test()
    {
        InitializeComponent();
        this.Disposed += new EventHandler(test_Disposed);
    }

    void test_Disposed(object sender, EventArgs e)
    {
        if(clean!=textBox1.Text)
            MessageBox.Show("Do you want save form?");
    }

    private void test_Load(object sender, EventArgs e)
    {
        clean = textBox1.Text;
    }
}

和一个称为测试用户控件的父表单/>

and a parent form which call "test" user control

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void radButton1_Click(object sender, EventArgs e)
    {
        DocumentWindow DW_test = new DocumentWindow();
        DW_test.Text = "something";
        DW_test.Name = "test";
        DW_test.CloseAction = DockWindowCloseAction.CloseAndDispose;
        var Frm = new test();
        Frm.Dock = DockStyle.Fill;
        DW_test.Controls.Add(Frm);
        this.radDock1.AddDocument(DW_test);
        this.radDock1.ActiveWindow = DW_test;
        Frm.Show();
    }
}

我想在Test usercontrol关闭时，将textbox的新值与旧值进行比较。但在处理事件时总是textbox.tex ==

但我没有手动更改文本框的值。问题是什么？

I want when Test usercontrol is closing,the new value of textbox be compared with old valu of that. but in disposing event always is textbox.tex==""
but I didnt change value of textbox manually. whats the problem?

推荐答案

你应该使用用户控制父关闭事件来管理你的工作，而不是使用 Dispose ，因为当 Dispose 将被调用时将会延迟。



所以在你的测试用户控件加载事件，你应该在下面的例子中做：

You should use the user control parent Closing event to manage your job and not to use Dispose, because when Dispose will be invoked will be to late.

So in you test user control Load event you should do like in the example bellow:

private void test_Load(object sender, EventArgs e)
{
clean = textBox1.Text;
((Form)this.Parent).Closing += new CancelEventHandler(ParentClosing);
}

private void ParentClosing(object sender, CancelEventArgs e)
{
if(clean!=textBox1.Text)
      MessageBox.Show("Do you want save form?");
//...
}

我知道你在这里使用Telerik Controls，我不确定是否在这种情况下引入了独特：这里显示的代码是我在Windows Forms中编写的代码。



关闭'Disposed正在执行之后 WindowDocument关闭并且'Dispose处理程序已执行：所以，任何控件的内容在其中，控件内的控件等，就像UserControl中的TextBox一样......已经消失了。



我强烈建议你处理WindowDocument的'关闭在您的UserControl中有一个简单的公共变量（或属性），当父关闭时，它的父容器将访问它：

I'm aware you are using Telerik Controls here, and I am not sure if that introduces anything "unique" into this situation: the code shown here is what I would write in Windows Forms.

Your code for 'Disposed is executing after the WindowDocument is closed and its 'Dispose handler has executed: so, the contents of any Controls within it, and the Controls within Controls, etc., like a TextBox in a UserControl, are ... gone.

I strongly suggest you handle the WindowDocument's 'Closing event, and have a simple public variable (or Property) in your UserControl that will be accessed by its Parent container when the Parent closes:

// in the UserControl
// get rid of the 'Dispose stuff
public bool IsDirty()
{
    return textBox1.Text != clean;
}

并且，在Form / DocumentWindow中：

And, in the Form/DocumentWindow:

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
    if (test1.IsDirty)
    {
        if (ShowDialog("Do you want save form?") == DialogResult.Yes)
        {
            // save whatever ?
            // your code to save
        }
        else
        {
            // cancel the Form Closing ?
            e.Cancel = true;
        }
    }
}

我发现您使用'测试用户控件的名称，并在表单代码中使用对于'DocumentWindow实例的变量名非常混乱，我预测这会让任何试图使用/读取代码的人感到困惑......包括你在看代码时的自己在将来。



它不会花费任何使用描述性唯一名称的东西，它是一个发展的重要技能/习惯。

I find your use of 'test for both the name of the UserControl, and in the Form code as a variable name for an instance of 'DocumentWindow is very confusing, and I predict this will be a source of confusion for anyone trying to use/read your code ... including yourself when you look at your code in the future.

It doesn't cost you anything to use descriptive unique names, and it's an important skill/habit to develop.

这篇关于在关闭usercontrol之前提示保存值的问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！