C# – Calling public method of user control from a parent form

cc#-4.0user-controlswinforms

I have form containing a Clear Button, usercontrol. The userControl has some text box and labels.

On the click of clear button the entries in the textbox should get cleared.

I have written a public method in userControl class which clears entries on from text box.

How to call this clear() method from clicking clear button from parent form?

Best Answer

your Clear() method should be something like this

//this method in the userControl
public void Clear()
{
   //Clear your text box
   this.txtbox1.Text = string.Empty;
   //Do other clean-up things if you want
}

now in your parent form, use your userControl name (you must add the userControl to your parent form) and call this code upon clicking the button event

private void button1_Click(object sender, EventArgs e)
{
   //Call the Clear method from the UserControl
   yourUserControlName.Clear();
}

otherwise, please share your code.

Related Solutions

C# – Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

As per Prerak K's update comment (since deleted):

I guess I have not presented the question properly.

Situation is this: I want to load data into a global variable based on the value of a control. I don't want to change the value of a control from the child thread. I'm not going to do it ever from a child thread.

So only accessing the value so that corresponding data can be fetched from the database.

The solution you want then should look like:

UserContrl1_LOadDataMethod()
{
    string name = "";
    if(textbox1.InvokeRequired)
    {
        textbox1.Invoke(new MethodInvoker(delegate { name = textbox1.text; }));
    }
    if(name == "MyName")
    {
        // do whatever
    }
}

Do your serious processing in the separate thread before you attempt to switch back to the control's thread. For example:

UserContrl1_LOadDataMethod()
{
    if(textbox1.text=="MyName") //<<======Now it wont give exception**
    {
        //Load data correspondin to "MyName"
        //Populate a globale variable List<string> which will be
        //bound to grid at some later stage
        if(InvokeRequired)
        {
            // after we've done all the processing, 
            this.Invoke(new MethodInvoker(delegate {
                // load the control with the appropriate data
            }));
            return;
        }
    }
}

C# – How to return a value from a Form in C#

Create some public Properties on your sub-form like so

public string ReturnValue1 {get;set;} 
public string ReturnValue2 {get;set;}

then set this inside your sub-form ok button click handler

private void btnOk_Click(object sender,EventArgs e)
{
    this.ReturnValue1 = "Something";
    this.ReturnValue2 = DateTime.Now.ToString(); //example
    this.DialogResult = DialogResult.OK;
    this.Close();
}

Then in your frmHireQuote form, when you open the sub-form

using (var form = new frmImportContact())
{
    var result = form.ShowDialog();
    if (result == DialogResult.OK)
    {
        string val = form.ReturnValue1;            //values preserved after close
        string dateString = form.ReturnValue2;
        //Do something here with these values

        //for example
        this.txtSomething.Text = val;
    }
}

Additionaly if you wish to cancel out of the sub-form you can just add a button to the form and set its DialogResult to Cancel and you can also set the CancelButton property of the form to said button - this will enable the escape key to cancel out of the form.

Best Answer

Related Solutions

C# – Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on

C# – How to return a value from a Form in C#

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