Question

每当点击一个按钮时，我通常会调用这段代码来显示表单。

    private frmSelection _frmSelection;`

    private void _frmSelection_FormClosing(object sender, FormClosingEventArgs e)
    {
        _frmSelection = null;
    }

    private void changeFeedOrderToolStripMenuItem_Click(object sender, EventArgs e)
    {
        if (_frmSelection == null)
        {
            _frmSelection = new frmSelection();
            _frmSelection.FormClosing += _frmSelection_FormClosing;
            _frmSelection.WindowState = FormWindowState.Minimized;
            _frmSelection.Show();
            _frmSelection.WindowState = FormWindowState.Normal;
        }
        else
        {
            _frmSelection.WindowState = FormWindowState.Minimized;
            _frmSelection.WindowState = FormWindowState.Normal;
        }
    }

如果表单已经打开，它将显示已打开的实例，而不是创建新实例。它运作正常。
但我的问题是我需要复制粘贴并在添加新表单时更改表单名称如何推广和添加的辅助类？

Answer 1

这样的事情：

public sealed class ReusableFormContainer<T> : IDisposable
    where T : Form, new()
{
    private bool isDisposed;

    private void HandleFormClosing(object sender, FormClosingEventArgs e)
    {
        Form = null;
    }

    public T Form { get; private set; }

    public void Show()
    {
        if (isDisposed)
        {
            throw new ObjectDisposedException(null);
        }

        if (Form == null)
        {
            Form = new T { WindowState = FormWindowState.Minimized };
            Form.FormClosing += HandleFormClosing;
            Form.Show();
        }
        else
        {
            Form.WindowState = FormWindowState.Minimized;
        }

        Form.WindowState = FormWindowState.Normal;
    }

    public void Dispose()
    {
        // IDisposable.Dispose is implemented to handle cases, when you want to close
        // wrapped form using code
        if (!isDisposed)
        {
            Form?.Dispose();
            isDisposed = true;
        }
    }
}

用法：

// must be initialized somewhere in constructors
private readonly ReusableFormContainer<FormA> container_A;
private readonly ReusableFormContainer<FormB> container_B;

private void button1_Click(object sender, EventArgs e)
{
    container_A.Show();
}

private void button2_Click(object sender, EventArgs e)
{
    container_B.Show();
}

Answer 2

以下代码可能会执行您想要的操作。只是考虑使用Application函数，因为它们可以涵盖线程上的所有表单。

    public partial class Form1 : Form
{
    public int i; 

    private Form1 _frmSelection;

    public Form1()
    {
        InitializeComponent();
        i = Application.OpenForms.Count;

    }
private void _frmSelection_FormClosing(object sender, FormClosingEventArgs e)
    {
        _frmSelection = null;
    }


    private void button1_Click(object sender, EventArgs e)
    {

        if (_frmSelection == null)
        {

            _frmSelection = new Form1();

            _frmSelection.FormClosing += _frmSelection_FormClosing;
            _frmSelection.WindowState = FormWindowState.Minimized;
            _frmSelection.WindowState = FormWindowState.Normal;
            _frmSelection.Show();

            if (Application.OpenForms.Count > 1)
            {

                _frmSelection.Text = Application.OpenForms[i].Text + " and going";
            }


        }
        else
        {
            _frmSelection.WindowState = FormWindowState.Minimized;
            _frmSelection.WindowState = FormWindowState.Normal;

        }
    }
}

在按钮事件中推广表单调用

2 个答案: