Keeping a DropDownList's DataSource Updated

The DropDownList does not manage selected state like other controls. Therefore, I use a Session variable to store an index to keep track of the currently selected item:

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            Session["listId"] = ddlList.SelectedValue;
            GridViewStocksInLists.DataBind();
        }
    }

Now, I add the SelectedIndexChanged event with the following code:

    protected void ddlList_SelectedIndexChanged(object sender, EventArgs e)
    {
        Session["listId"] = ddlList.SelectedValue;
        GridViewStocksInLists.DataBind();
    }

Reference: http://www.velocityreviews.com/forums/t123449-problem-with-formview-and-dropdownlists.html

Use a CustomControl to Set UserId and Use as a DataBindable Property

Use a CustomControl (named MembershipUser) to Set UserId and Use as a DataBindable Property. Create a MembershipUser CustomControl that has a property named Value that can be DataBound. For example MembershipUser1.Value would fetch the userId:

    [Browsable (true)]
    public string Value
    {
        get
        {
            MembershipUser currentUser;
            currentUser = Membership.GetUser();
            if (currentUser == null)
                return string.Empty;
            return currentUser.ProviderUserKey.ToString();
        }
    }

Reference: This is from http://aspnet.4guysfromrolla.com/articles/110106-1.aspx

Be Careful About uniqueId Parameter in Stored Procedure

Here is an error I received when my UniqueId parameter in a stored procedure was not valid:

Server Error in '/stockmonger.com' Application.
Conversion failed when converting from a character string to uniqueidentifier.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: Conversion failed when converting from a character string to uniqueidentifier.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

I corrected to make sure the parameter was a valid uniqueId paramater and not null.

Multiple PostBack problem with GridView

I noticed my SelectedIndexChanged method being called twice in IE7 when I selected a gridview row. I used solution 2 at http://www.codeproject.com/KB/aspnet/GVImageCommandButtonProb.aspx to solve the problem.