You can protect against this case by also checking the value of Control.IsHandleCreated when Control.InvokeRequired returns false on a background thread. This might cause the control's handle to be created on the background thread, isolating the control on a thread without a message pump and making the application unstable. In the case where the control's handle has not yet been created, you should not simply call properties, methods, or events on the control. This means that Control.InvokeRequired can return false if Control.Invoke(Delegate) is not required (the call occurs on the same thread), or if the control was created on a different thread but the control's handle has not yet been created. If no appropriate handle can be found, the Control.InvokeRequired method returns false. If the control's handle does not yet exist, Control.InvokeRequired searches up the control's parent chain until it finds a control or form that does have a window handle. For all other method calls, you should use one of these invoke methods when calling from a different thread. Calling Control.CreateGraphics before the control's handle has been created on a background thread can cause illegal cross thread calls. Any resemblance to other material is an un-intentional coincidence and should not be misconstrued as malicious, slanderous, or any anything else hereof.In addition to the Control.InvokeRequired property, there are four methods on a control that are thread safe to call: Control.Invoke(Delegate), Control.BeginInvoke(Delegate), Control.EndInvoke(IAsyncResult) and Control.CreateGraphics if the handle for the control has already been created. This article is entirely original, unless specified. This article should not be construed as the best practices white paper. NOTE: This article is purely for demonstration. errorProvider1.SetError(dateTimePicker1, "" ).errorProvider1.SetError(dateTimePicker1, "Appointment cannot be scheduled in the weekend. Please select a weekday" ).errorProvider1.SetError(textBox2, "Please enter your age as a number" ).errorProvider1.SetError(textBox2, "You must be atleast 18 years old to setup a test" ).errorProvider1.SetError(textBox2, "" ).errorProvider1.SetError(textBox2, "Please enter your Age" ).errorProvider1.SetError(textBox1, "" ).errorProvider1.SetError(textBox1, "Please enter your Name" ).MessageBox.Show( "Please enter valid data" ).MessageBox.Show( "Appointment will be created now" ).if (bValidName & bValidAge & bValidTestDate).bool bValidTestDate = ValidateTestDate().private void button1_Click( object sender, System.EventArgs e).private void dateTimePicker1_Validating( object sender, e). private void textBox2_Validating( object sender, e).private void textBox1_Validating( object sender, e).errorProvider1.ContainerControl = this.private void Form1_Load( object sender, System.EventArgs e).private void label1_Click( object sender, System.EventArgs e).button1.Click += new System.EventHandler( this. label4.Text = "Setup Driving Test Appointment" dateTimePicker1.Validating += new ( this. dateTimePicker1.Name = "dateTimePicker1" label1.Click += new System.EventHandler( this.
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