Inside for loop if condition not working?

I am trying to get Data from database to text box on select index changed i am getting output, But i use simple if statement inside my loop but its not working where am i doing wrong Please help me ??

let me explain I use two text box txtEmployeeNumber and txtEmployeename on txtEmployeeNumber_TextChanged i have written my logic code

 protected void txtEmployeeNumber_TextChanged(object sender, EventArgs e)
        {
            string EmployeeNo = "";
            string EmployeeName = "";
            int Row = 0;
            foreach (GridViewRow row in grdRegister.Rows)
            {
                if (row.RowType == DataControlRowType.DataRow)
                {
                    EmployeeNo = (row.Cells[1].FindControl("txtEmployeeNumber") as TextBox).Text;
                }
                DataTable dt = new DataTable();
                dt = (DataTable)Application["Employee_details"];
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    if (dt.Rows[i]["Employee_ID"].ToString() == EmployeeNo)
                    {
                        (row.Cells[2].FindControl("txtEmployeeName") as TextBox).Text = dt.Rows[i]["Employee_Name"].ToString();
                        EmployeeName = (row.Cells[2].FindControl("txtEmployeeName") as TextBox).Text;
                        break;
                    }
                    else if ((row.Cells[2].FindControl("txtEmployeeName") as TextBox).Text == "")
                    {
                        ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "Error", "alert('No Data Found...')", true);
                    }
                }
            }
        }