Receiving Messages with Session Integrator for LU2

After you create an LU2 session, you can retrieve information and messages from the 3270 console through the Microsoft.HostIntegration.SNA.Session.ScreenData and Microsoft.HostIntegration.SNA.Session.SessionDisplay objects.

Receive information over an LU2 connection

1. If necessary, retrieve the entire screen as a screen dump using Microsoft.HostIntegration.SNA.Session.ScreenData.

   For most circumstances, retrieving all the information on the screen is not necessary. Instead, you can use the Microsoft.HostIntegration.SNA.Session.SessionDisplay object for most applications.

2. Get the location of the cursor with a call to Microsoft.HostIntegration.SNA.Session.ScreenCursor.

3. Optionally, you can get the location and information contained within different fields on the screen with a call to one of the Microsoft.HostIntegration.SNA.Session.SessionDisplay.GetField%2A or Microsoft.HostIntegration.SNA.Session.SessionDisplay.GetFields%2A methods, or the Microsoft.HostIntegration.SNA.Session.SessionDisplay.CurrentField%2A property.

   Microsoft.HostIntegration.SNA.Session.SessionDisplay.GetField%2A and Microsoft.HostIntegration.SNA.Session.SessionDisplay.GetFields%2A both contain multiple overloads, allowing you to retrieve field information from the screen, depending on what information you provide. In contrast, Microsoft.HostIntegration.SNA.Session.SessionDisplay.CurrentField%2A represents only the field the cursor is currently in.

4. Finally, you can receive field update information with a call to the various SessionDisplay.Wait methods.

Example

The following code is from the 3270 application in the Host Integration Server SDK. The sample uses SessionDisplay.CurrentField.Data to access the screen data.

private void PerformTX_Click(object sender, EventArgs e)  
        {  
            try  
            {  
                // Disable every button and text box.  
                DisableEverything();  
  
                m_Handler.SendKey("@E");  
                TraceScreen();  
  
                // Wait for screen to calm down.  
                m_Handler.WaitForSession(SessionDisplayWaitType.NotBusy, 5000);  
                TraceScreen();  
  
                // See if the Balance Field is filled out.  
                m_Handler.Cursor.Row = m_row;  
                m_Handler.Cursor.Column = m_column;  
                TraceScreen();  
                // Tab to the Account Number field.  
                m_Handler.SendKey("@T");  
                TraceScreen();  
                // Move to the Next Field (Empty Stuff after 123456).  
                m_Handler.MoveNextField();  
                TraceScreen();  
                // Move to the Next Field (Title, Account Balance).  
                m_Handler.MoveNextField();  
                TraceScreen();  
                // Move to the Next Field (Account Balance).  
                m_Handler.MoveNextField();  
                TraceScreen();  
  
                // Extract Data from this field.  
                string accountBalance = m_Handler.CurrentField.Data;  
  
                // Trim the string.  
                accountBalance = accountBalance.Trim();  
  
                // Only things to do now are clear screen or disconnect.  
                EnableClearScreen();  
  
                // If we failed (not Abended) then this field will be blank.  
                if (accountBalance.Length == 0)  
                    throw new Exception("Failed to get Account Balance");  
                else  
                    MessageBox.Show(accountBalance, "Account Balance");  
            }  
            catch (Exception ex)  
            {  
                MessageBox.Show(ex.Message);  
            }  
        }  

See Also

Session Integrator for LU2
Session Integrator for LU0