Hello Folks,

I couldn't find an appropriate solution on these forums for my situation hence I am creating a new post.

My setup: MasterPage has UpdatePanel, Default.aspx is wired to the Master page, Default.aspx page has Ajax Tab container. I load a UserControl in one of the Tabs on Default.aspx page, works great. But when I try to add something a PlaceHolder in the UserControl on Page_Load of the UC, I get "Exception has been thrown by the target of an invocation.". Also when I step through it seems that the UserControl already is postback and if (!Page.IsPostBack) does not fire.

Default.aspx 

  protected void btnContinue_Click(object sender, EventArgs e)
    {
        Control ctrl = LoadControl("~/Forms/myControl.ascx", tbCustNumber.Text);
        ctrl.ID = "ucCust";
        
        // Initialize Tab
        TabContainer tc = (TabContainer)CommonUtility.FindControlRecursive(this, "tcDefault");
        TabPanel tab = (TabPanel)tc.FindControl("tabCust");// new TabPanel();
        tab.Controls.Add(ctrl);        
    }
   

private UserControl LoadControl(string UserControlPath, params object[] constructorParameters)
    {
        System.Collections.Generic.List constParamTypes = new System.Collections.Generic.List();
        foreach (object constParam in constructorParameters)
        {
            constParamTypes.Add(constParam.GetType());
        }

        UserControl ctl = Page.LoadControl(UserControlPath) as UserControl;

        // Find the relevant constructor
        System.Reflection.ConstructorInfo constructor = ctl.GetType().BaseType.GetConstructor(constParamTypes.ToArray());

        //And then call the relevant constructor
        if (constructor == null)
        {
            throw new MemberAccessException("The requested constructor was not found on : " + ctl.GetType().BaseType.ToString());
        }
        else
        {
            try
            {
                constructor.Invoke(ctl, constructorParameters);
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        // Finally return the fully initialized UC
        return ctl;
    }

1        private string _custNumber;
2        public string CustNumber
3        {
4            get { return _custNumber; }
5            set { _custNumber = value; }
6        }
7    	
8    	public Forms_Loan() { }
9    
10       public Forms_Loan(string custNumber)
11       {
12           CustNumber = custNumber; // Add to Control Property
13           LoadCustomer(custNumber);
14       }
15   	
16   	protected void Page_Load(object sender, EventArgs e)
17       {
18           if (!Page.IsPostBack)
19               LoadCustomer(custNumber);
20       }
21   	
22   	private void LoadCustomer(string custNumber)
23       {
24           // Bind DataGrid with customer information
25   	}

PlaceHolder plh = Page.FindControl("plhLoan") as PlaceHolder;
plh.Controls.Add("something");

I get the same error.

Any help would be appreciated in trying to get my dynamic user controls working. Perhaps I need a better understanding with examples on how this all works.

"when I step through it seems that the UserControl already is postback"

Seems to make sense to be in postback, it is happening in btnContinue_Click...

I would suggest using properties rather than that construtor trick.