The line reader.Read() is missing in your code. You should add it. It is the function which actually reads data from the database:
string conString = "Data Source=localhost;Initial Catalog=LoginScreen;Integrated Security=True";
SqlConnection con = new SqlConnection(conString);
string selectSql = "select * from Pending_Tasks";
SqlCommand com = new SqlCommand(selectSql, con);
try
{
con.Open();
using (SqlDataReader read = cmd.ExecuteReader())
{
while(reader.Read())
{
CustID.Text = (read["Customer_ID"].ToString());
CustName.Text = (read["Customer_Name"].ToString());
Add1.Text = (read["Address_1"].ToString());
Add2.Text = (read["Address_2"].ToString());
PostBox.Text = (read["Postcode"].ToString());
PassBox.Text = (read["Password"].ToString());
DatBox.Text = (read["Data_Important"].ToString());
LanNumb.Text = (read["Landline"].ToString());
MobNumber.Text = (read["Mobile"].ToString());
FaultRep.Text = (read["Fault_Report"].ToString());
}
}
}
finally
{
con.Close();
}
EDIT : This code works supposing you want to write the last record to your textboxes. If you want to apply a different scenario, like for example to read all the records from database and to change data in the texboxes when you click the Next button, you should create and use your own Model, or you can store data in the DataTable and refer to them later if you wish.