drawing a red border on or around a control in winforms

I want to highlight the controls that need to be filled in when a user does not enter information - for example a red border - how can I achieve this in a win form?

 string msg = "";
                    if (comBoxToLocations.SelectedValue.ToString() != "-1" && comBoxToLocations.SelectedValue.ToString() != "3")
                    {
                        ToID = Convert.ToInt32(comBoxToLocations.SelectedValue.ToString());
                    }
                    else
                    {
                        if (comBoxToLocations.SelectedValue.ToString() == "-1")
                        {
                            msg += "You must select a location to send to\r\n";
                        }
                        if (comBoxToLocations.SelectedValue.ToString() == "3")
                        {
                            msg += "Location cannot be Unknown\r\n";
                        }
                    }
                    if (cmboCarrier.SelectedValue.ToString() != "-1")
                    {
                        carrierID = Convert.ToInt32(cmboCarrier.SelectedValue.ToString());
                    }
                    else
                    {
                        msg += "You must select a carrier\r\n";
                    }
                    if (string.IsNullOrEmpty(trackingNumber))
                    {
                        msg += "You must enter a tracking number\r\n";
                    }
                    if (expecteddate == today)
                    {
                        msg += "Your Expected arrival date is too short\r\n";
                    }
                    if (msg != "")
                    {
                        MessageBox.Show(msg);
                        return;
                    }

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LVL 6

r3nderAsked: 2014-12-15

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Solutions

LVL 1

psdesignadminConnect With a Mentor Commented: 2014-12-15

Most of the Winform controls have a property BorderStyle that allows for a border to be shown around that control. But the look and feel of that border cannot be changed. And there are controls (button, groupbox, etc.) that do not have this property. So there is no direct way of adding a Border around these controls

The following magic lines allow us to add a border around a control:

public class MyGroupBox : GroupBox
{
   protected override void OnPaint(PaintEventArgs e)
   {
     base.OnPaint(e);
     ControlPaint.DrawBorder(e.Graphics, ClientRectangle,
                                  Color.Red, BORDER_SIZE, ButtonBorderStyle.Inset,
                                  Color.Red, BORDER_SIZE, ButtonBorderStyle.Inset,
                                  Color.Red, BORDER_SIZE, ButtonBorderStyle.Inset,
                                  Color.Red, BORDER_SIZE, ButtonBorderStyle.Inset);
   } 
}

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The ControlPaint class allows to add a border around a control. The above call can be invoked in a Paint event handler of a control.

~Tim

LVL 86

Mike TomlinsonMiddle School Assistant TeacherCommented: 2014-12-15

Have you considered using the standard ErrorProvider control? Very easy to use...
http://msdn.microsoft.com/en-us/library/aa983609(v=vs.71).aspx

You can set an initial error with:

errorProvider1.SetError(comboBox1, "Please select a value!");

And clear it with:

errorProvider1.SetError(comboBox1, "");