Question

1. how can i clear the datagridview once i click on the cancel button.It will start the process from starting but before starting new thread i need to clear the datagrid view ever time.

2. th.Suspend(),th.Resume(),th.Abort() // this is obsolete.
   This has been deprecated. I get these kind of warnings.but still the code i use works okay for me.I never worked on Threads before.

when ever i use Reset(),set() methods it doesnt work. may be i couldnt get idea to use them in a right way. Any suggestion to use in correct way?

ManualResetEvent run=new ManualResetEvent(true); 
ManualResetEvent shut=new ManualResetEvent(false);     
public delegate void GridTestResults(int Sno,string Name,double MinValue,double MaxValue,double Value,string Result,string Time);


public void ValuesToGrid(int Sno,string Name,double MinValue,double MaxValue,double Value,string Result,string Time)
{
    DataRow row=table.NewRow();
    if(this.InvokeRequired)
    {
        GridTestResults grid = new GridTestResults(this.ValuesToGrid);
        this.Invoke(grid,new object[]{Sno,Name,MinValue,MaxValue,Value,Result,Time});
    }
    else
    {
        row["Sno"] = Sno;
        row["Name"] = Name;
        row["MinValue"] = MinValue;
        row["MaxValue"] = MaxValue;
        row["Value"] = Value;
        row["Result"] = Result;
        row["Time"] = Time;
        table.Rows.Add(row);

        dataGridView1.Refresh();

        //How can i clear all the rows of gridview once the
        // its clicks the start button after cancel button
    }
}

 private void Startbutton_Click(object sender, EventArgs e)
{ 
    stopwatch.Start();
    timer1.Start();
    ts=new ThreadStart(ProcessStarted);
    th=new Thread(ts);                 
    th.Start();            
}

private void Pausebutton_Click(object sender, EventArgs e)
{                  
    if (th.ThreadState == System.Threading.ThreadState.Suspended)
    {
        timer1.Enabled = true;
        label5.Enabled = true;
        Pausebutton.Enabled = true;
        th.Resume();  //run.Set(); // this is obsolete.This has been deprecated.
        label3.Text = "The Current thread has resumed again";
    }
    else
    {
        label5.Enabled = false;
        timer1.Enabled = false;
        th.Suspend();  
        //th.Suspend(); // this is obsolete.This has been deprecated.
        label3.Text = "The current thread suspended";
    }
}

private void Cancelbutton_Click(object sender, EventArgs e)
{
    timer1.Stop();
    stopwatch.Stop();

    if (th.ThreadState==System.Threading.ThreadState.Suspended)
    {
         try
        {
             th.Abort();
        }
        catch (Exception)
        {
             th.Resume();
        }

    }
    try
    {
        th.Abort();
        //th.Join();
    }
    catch (Exception)
    {
        th.Resume();
    }
    label3.Text = "The Testprocess stopped completely";

    //dataGridView1.Rows.Clear();
    //dataGridView1.DataSource = null;  
    //i cannot use any of these two way to clear the gridview....
    //gives error like cannot clear the list
    stopwatch.Reset();    
}

private void ProcessStarted()
{
    //all the methods to be shown in datagridview 

void oneMethod()
{
    Application.Run(new OneForm()); 
    //here the form appears as popup window.once
    // we click ok button it will closes automatically.
    //now the problem is when ever i clcik pause button the OneForm will 
    // hangs and when i clcik resume it will work normally.
    // am not sure is it the correct way of doing r not while 
    // working with the threads?
}

    //dataGridView1.Rows.Clear(); 
    //Here also it does not work..gives same exception like 
    //cannot clear the list.
}

Answer 1

Use Datatable clear() to clear the rows of Datatable.