Reset the edit mode of gridview on cancel button click.
Try :
protected void BtnCancel_Click(object sender, EventArgs e)
{
objBAL = new ApplicationLogic();
objBAL.ClearAllControls(Page);
_Status = optype.insert;
EnabelOrDisable();
SmtBranchName.Focus();
SetGridHeaderFix();
SmtBranchGrid.EditIndex = -1;
}
--Amit