Changing parameters using for loop - transaction does not commit

[vincentBS4G4]

Hi

I'm trying to change parametervalues of the profile of a wallsweep programmatically (the user clicks on a wallsweep, the parameters of the profile are loaded into a form & the user can modify the parameters). Now to change multiple parametervalues of the profile at once I'm using a for loop enclosed in a transaction. The problem is that the transaction does not seem to commit and the for loop does not loop over all values. 

I guess it's probably an issue with the transaction?

Thanks in advance 🙂

public void Execute(UIApplication app)
        {
            string eID = this.savedelementid;//retrieving the unique id saved using another externaleventhandler
                    
            Element el = app.ActiveUIDocument.Application.ActiveUIDocument.Document.GetElement(eID); // retrieving the wallsweep element - (works fine)
                  
            WallSweep ws;
            WallSweepInfo wsi;


            List<Parameter> lp; 
            List<String> ls; 

            lp = this.SetParameter;// list of parameters of the wall sweep obtained using another externaleventhandler - (works fine)
            ls = this.SetValue;// list of parameter values of the wall sweep obtained using another externaleventhandler - (works fine)
          
            if (el is WallSweep)
            {                
                ws = (WallSweep)el;

                wsi = (WallSweepInfo)ws.GetWallSweepInfo();
                Element wsprofile = app.ActiveUIDocument.Application.ActiveUIDocument.Document.GetElement(wsi.ProfileId);  // retrieving the profile elmement of the wall sweep- (works fine)
                TaskDialog.Show("melding", wsprofile.Name.ToString()); // prints out the correct name
               
                using (Transaction transaction = new Transaction(app.ActiveUIDocument.Application.ActiveUIDocument.Document))
                    {

                    if (transaction.Start("change dimension") == TransactionStatus.Started)
                    {
                   
                        for (int i = 0; i < lp.Count; i++)
                        {
                            MessageBox.Show(i.ToString()); // only prints out 0 and 1, while lp.Count = 20?
                            wsprofile.LookupParameter(lp[i].Definition.Name).SetValueString(ls[i]);
                            
                        };                        app.ActiveUIDocument.Application.ActiveUIDocument.Document.Regenerate();
                        transaction.Commit(); //does not commit the changes

                    };
                                                            
                }
            }               
        }
    }

[RPTHOMAS108 · Accepted solution]

1) Are all of the parameter you are processing settable (.IsReadOnly = false)

2) Can they all be set with a string value, usually SetValueString would be related to parameters of storage type double.

3) Is this being executed from within a try/catch structure (do you get any exceptions relating to setting the parameters).

LookupParameter is not a good thing to use to find the right parameters. i.e. some built-in parameters are guilty of having duplicate names.

[vincentBS4G4]

Yes, this was the issue. The try/catch gave the error "an object reference not set to an instance of an object" so not all parameters were modifiable. Thanks!