How to show waiting Gif image during form load event

Question

i have one form which is doing some long process on form load event, So i want to show One Gif image "Please Wait" during form load event.

below is code.

private void frmWaitShow()
        {
            try
            {
                frmWaitwithstatus objWait = new frmWaitwithstatus();// this form has Gif Image for Processing
                objWait.lblStatus.Text = "Processing Request, Please wait...";
                objWait.ShowDialog();
            }
            catch (Exception ex)
            {
                Logger.SystemException(ex);
                Logger.FTSError(" ERROR :" + ex.Message + "frmTest || frmWaitShow");

            }
        }


        Thread oThread;
        private void frmTest_Load(object sender, EventArgs e)
        {
            try
            {


                oThread = new Thread(new ThreadStart(frmWaitShow));
                oThread.Start();

                //Functions for Connection with devices
                if (LoadDatafromDB() == false) return;
                if (ElectTestLoad() == false) return;
                if (PowerOnSelfTest() == false) { return; }
                InitiControlsElectTest();
                SetSystemMode(SystemMode.ElectricalMode);

                oThread.Abort();
            }
            catch (Exception ex)
            {
                oThread.Abort();
                Logger.SystemException(ex);

            }
        }

after Thread.start() my debugger go one one step in each thread main and one i created but after it go to below line.

frmWaitwithstatus.cs constructor first line

public frmWaitwithstatus()

it stop execute my Thread and execute all function of main thread once Main Thread execution complete after then only it start execute my thread (which is Gif processing image).

Answer 1

Using the async/await pattern will made this an easy task and every form will work on UI thread:

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

    private async void Form1_Load(object sender, EventArgs e)
    {
        // async show loading form dialog
        var loadingForm = new LoadingForm();
        var loadingDialogTask = this.InvokeAsync(loadingForm.ShowDialog);

        // async loading data
        var data = await LoadDataAsync();
        listBox1.DataSource = data;

        loadingForm.Close();
        await loadingDialogTask;
    }

    private async Task<ICollection<string>> LoadDataAsync()
    {
        // fake work load
        await Task.Delay(4000).ConfigureAwait(false);
        return Enumerable.Range(1,20000).Select(e => e.ToString()).ToList();
    }

}

Needed async extension for the controls:

public static class ControlAsyncExtensions
{
    public static Task InvokeAsync(this Control control, Action action)
    {
        var tcs = new TaskCompletionSource<bool>();
        control.BeginInvoke(new Action(() =>
        {
            try
            {
                action();
                tcs.SetResult(true);
            }
            catch (Exception ex)
            {
                tcs.SetException(ex);
            }
        }
        ));
        return tcs.Task;
    }

    public static Task<T> InvokeAsync<T>(this Control control, Func<T> action)
    {
        var tcs = new TaskCompletionSource<T>();
        control.BeginInvoke(new Action(() =>
        {
            try
            {
                tcs.SetResult(action());
            }
            catch (Exception ex)
            {
                tcs.SetException(ex);
            }
        }
        ));
        return tcs.Task;
    }
}