Question

我有2个表格，第一个 - 主要，第二个孩子，从thred打开。如果儿童表格已经打开，我需要打开儿童表格，关闭它并只显示一个儿童表格。

主要形式：

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

    private void showChildForms(object sender, EventArgs e)
    {
        createThread();
        createThread();
        createThread();
    }

    private  void createThread()
    {
        var t = new Thread(
               () =>
               {
                   this.Invoke(new Action(delegate
                   {

                       showForm();
                   }));
               }
               );
        t.IsBackground = true;
        t.Start();
    }

    private void showForm()
    {
        var form2 = new ChildForm();
        form2.ShowDialog();
    }
}

儿童形式：

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

Answer 1

首先，你的问题对我来说并不是很清楚。但.. 一种简单的方法是在它们之间共享一个bool。另一个提示：当你完成它时，总是处理你的形式。这里的主题是浪费资源......你应该过度思考你的方法。

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

    public bool ChildIsOpen {get; set;}

    private void showChildForms(object sender, EventArgs e)
    {
        createThread();
        createThread();
        createThread();
    }

    private  void createThread()
    {
        if(ChildIsOpen)
             return;
        var t = new Thread(
               () =>
               {
                   this.Invoke(new Action(delegate
                   {

                       showForm();
                   }));
               }
               );
        t.IsBackground = true;
        t.Start();
    }

    private void showForm()
    {
        using (ChildForm childForm = new ChildForm())
        {
            childForm .Load += (o, args) => ChildIsOpen = true;
            childForm .Closed += (o, args) => ChildIsOpen = false;
            childForm .ShowDialog();
        }
    }
}

儿童形式（未改变）：

public partial class ChildForm : Form
{
    public ChildForm()
    {
        InitializeComponent();

    }

}

Answer 2

如果我的理解是对的。

如果不符合您的需求，请更清楚地评论您的要求

以您的主要表格

public partial class MainForm : Form
{

 var form2 = new ChildForm();

public MainForm()
{
    InitializeComponent();
}

private void showChildForms(object sender, EventArgs e)
{
    createThread();
    createThread();
    createThread();
}

private  void createThread()
{
    var t = new Thread(
           () =>
           {
               this.Invoke(new Action(delegate
               {

                   showForm();
               }));
           }
           );
    t.IsBackground = true;
    t.Start();
}

private void showForm()
{

     Form res = new Form();

        foreach (Form form in Application.OpenForms)
        {
            if (form.Text == "Form2")//or form.Name u can use how you are assigning in form2 
            {
                res = form;
                break;
            }
        }

        res.Close();

         // Do what ever.The above part will close the previous instances of the Forms.

}
}

在后台线程中显示的关闭子窗体

2 个答案: