如何在调用之前等待创建表单句柄？

问题描述

我有将一种格式的 csv 文件转换为另一种格式的 Windows 窗体项目。 我试图在转换时显示转换进度。 如果转换失败，转换方法会抛出异常。 转换失败时，我关闭 ConvertingScreen 但当我关闭 ConvertingScreen system.invalidOperationException 时发生。

在创建窗口句柄之前，不能在控件上调用 invoke 或 begininvoke

如果我在关闭之前添加一些等待，似乎永远不会发生。我曾尝试检查 HandleCreated，但效果不佳。我曾经通过在进行中仅添加可见标签来完成此类工作。这是我第一次这样做。这是不好的做法吗？如果不是，我该如何解决这个问题？下面是简单的代码，可以描述发生在我身上的一切。

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

    private void button1_Click(object sender,EventArgs e)
    {
        try
        {
            ConvertingScreen.ShowScreen();
            // Converts here and results in failure so throwing an exception
            throw new NotImplementedException();
        }
        catch (Exception)
        {
            ConvertingScreen.CloseForm();
            MessageBox.Show("error");
        }
    }
}

// ConvertingScreen
public class ConvertingScreen : Form
{
    public ConvertingScreen()
    {
        InitializeComponent();
    }

    private void InitializeComponent()
    {
        this.label1 = new System.Windows.Forms.Label();
        this.SuspendLayout();
        // label1
        this.label1.Font = new System.Drawing.Font("MS UI Gothic",11F,System.Drawing.FontStyle.Regular,system.drawing.graphicsUnit.Point,((byte)(128)));
        this.label1.Location = new System.Drawing.Point(12,9);
        this.label1.Name = "label1";
        this.label1.Size = new System.Drawing.Size(316,22);
        this.label1.TabIndex = 0;
        this.label1.Text = "";
        this.label1.TextAlign = System.Drawing.ContentAlignment.MiddleLeft;
        // ConvertingScreen
        this.BackColor = System.Drawing.Color.LightGray;
        this.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Center;
        this.ClientSize = new System.Drawing.Size(340,40);
        this.ControlBox = false;
        this.Controls.Add(this.label1);
        this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
        this.MaximizeBox = false;
        this.MaximumSize = new System.Drawing.Size(340,40);
        this.MinimizeBox = false;
        this.MinimumSize = new System.Drawing.Size(340,40);
        this.Name = "ConvertingScreen";
        this.ShowIcon = false;
        this.ShowInTaskbar = false;
        this.StartPosition = System.Windows.Forms.FormStartPosition.Manual;
        this.Text = "ConvertingScreen";
        this.TopMost = true;
        this.ResumeLayout(false);
    }

    private Label label1;

    private delegate void CloseDelegate();

    private delegate void UpdateTextDelegate(string text);

    private static ConvertingScreen form;

    public static void ShowScreen()
    {
        if (form != null) return;
        form = new ConvertingScreen();
        Thread thread = new Thread(new ThreadStart(ConvertingScreen.ShowForm));
        thread.SetApartmentState(ApartmentState.STA);
        thread.Start();
    }

    private static void ShowForm()
    {
        if (form != null) Application.Run(form);
    }

    public static void CloseForm()
    {
        form?.Invoke(new CloseDelegate(ConvertingScreen.CloseFormInternal));
    }

    private static void CloseFormInternal()
    {
        if (form != null)
        {
            form.Close();
            form = null;
        }
    }

    public static void Update(string text)
    {
        if (form != null) form.UpdateLabel(text);
    }

    private void UpdateLabel(string text)
    {
        if (Invokerequired)
        {
            this.Invoke(new UpdateTextDelegate(UpdateLabel),new object[] { text });
            return;
        }
        label1.Text = text;
    }
}

解决方法

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