Set TextBoxes Boarder Color

 Try This 

bool focus = false;
 private void Form1_Paint(object sender, PaintEventArgs e)
 { if (focus)
 {   
  textBox1.BorderStyle = BorderStyle.None;
 Pen p = new Pen(Color.Red);
 Graphics g = e.Graphics;
 int variance = 3; 
  g.DrawRectangle(p, new Rectangle(textBox1.Location.X - variance, textBox1.Location.Y - variance, textBox1.Width + variance, textBox1.Height +variance ));
 } 
else
 {    
   textBox1.BorderStyle = BorderStyle.FixedSingle;
 } 
}
 private void textBox1_Enter(object sender, EventArgs e)
 {             
  focus = true; this.Refresh(); 
  }
 private void textBox1_Leave(object sender, EventArgs e)
 {            
 focus = false; this.Refresh();
 }

refer original link for more information 

http://stackoverflow.com/questions/9768938/change-the-bordercolor-of-the-textbox

P.S Kindly explain All your requirement before submit the question.
 It will help to solve thread soon and save time of every person related to answer the question..

Hello Parveen,

As per your requirement, You need dynamic code to set the color of textboxs in your winform . 

Kindly check below code :

foreach(Control c in myForm.Controls) 
{ 
  if(c is TextBox) 
   { 
     ((TextBox)c).BorderStyle = yourStyle; 
   } 
}

if you required more help kindly follow the original thread in below link :

http://stackoverflow.com/questions/18865518/change-all-textbox-borderstyle-in-my-winform

Let me know if you required more help.