Grid View Troubles

[CaJack]

Hi, I’m having trouble with my grid view, I've search around and didnt find any help so I thought I'd post my problem. When the user is signed into my site and clicks button1, the users name is turned into a string and used in a query to display all the information for that user, but unfortunately it doesn’t work. It should output all the CD’s the user has input into the database. Here’s the code I have…

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim myString As String
         myString = Page.User.Identity.Name.ToString()
 
        Dim DBConn As New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=""|DataDirectory|\aspnetdb.mdf"";Integrated Security=True;User Instance=True")
 
        Dim DBCmd As New SqlCommand
        Dim DBAdap As New SqlDataAdapter
        Dim DS As New DataSet
        Dim dt As New DataTable
        DBConn.Open()
 
            DBAdap = New SqlDataAdapter("SELECT * FROM Table1 WHERE UserName = " & myString, DBConn)
 
            DBAdap.Fill(dt)
 
            GridView1.DataSource = dt
            GridView1.DataBind()
 
        DBCmd.Dispose()
        DBAdap.Dispose()
        DBConn.Close()
        DBConn = Nothing
    End Sub
 

When I run it this error comes up “SQLExeption was unhandled by usercode” and it also says “Invalid column name 'Rachel'.”. Rachel is actually the user I’m signed into the site and is the value in myString which is fine, but I don’t seem to see what the problem is. Could it be that UserName is set to NVARCHAR in the sql database? Can someone help me out, I’d really like to get this working. Any advice or help would be great.

Thanks,
CaJack