Load File From The Open Dialog box As Text Format Or As RTF Format...

It Will Ask You To Open File & Then It Will Open Your Selected File In RichTextBox...

string filename=null;         //On The Load Button's Click Event... private void btnLoad_Click(System.Object sender, System.EventArgs e) {        if (OpenFileDialog1.ShowDialog == DialogResult.OK) {               //Store Filename Into The Variable...               filename = OpenFileDialog1.FileName;               //Load Selected Text Format Or RTf Format File in RichTextBox... RichTextBox1.LoadFile(filename); } }