Question

I’m working with an asp.net website using C# in the background. I would like to be able to update an asp:label on a page, lets say Page1.aspx. I want this be updated depending on the outcome of a function in a class (.cs) in other folder. This could be behind.cs.

behind.cs

*some other code is here*
bool correct = false;
try
{
    if (_myConn.State == ConnectionState.Closed)
    {
        _myConn.Open();
        myCommand.ExecuteNonQuery();
    }
    if (Convert.ToInt32(myCommand.Parameters["@SQLVAR"].Value) < 1)
    {
        "Invalid Login" // I want to be the text of lblMessage.Text
    }
    else
    {
        correct = true;                 
    }
    _myConn.Close();
}
catch (Exception ex)
{
    "Error connecting to the database" // I want to be the text of lblMessage.Text
}
return correct;

page1.aspx

<asp:label runat="server" ID="lblMessage" cssClass="error"></asp:label>

How can I update the asp:label on page1.aspx* from **behind.cs??

Answer 1

You can’t directly access the label from another class.
You can write a TryLogin function that has an out parameter with the error message.

In Page1.cs

protected void BtnLogin_Clicked(object s, EventArgs e)
{
    string errMess;
    if(!Behind.TryLogin(out errMess)
       lblMessage.Text = errMess;
}

In behind.cs

public static bool TryLogin(out string errMess)
{
  *some other code is here*
  errMess = null;
  bool correct = false;
  try
  {
    if (_myConn.State == ConnectionState.Closed)
    {
        _myConn.Open();
        myCommand.ExecuteNonQuery();
    }
    if (Convert.ToInt32(myCommand.Parameters["@SQLVAR"].Value) < 1)
    {
        errMess = "Invalid Login" // I want to be the text of lblMessage.Text
    }
    else
    {
        correct = true;                 
    }
    _myConn.Close();
  }
  catch (Exception ex)
  {
    errMess = "Error connecting to the database" // I want to be the text of lblMessage.Text
  }
  return correct;
}