Querying with dynamic column name using SQLDataAdapter

Question

I am trying to dynamically change a query in a SQLDataAdapter based off the querystring. I tried passing it in as a parameter, but that doesn't work. Any other suggestions?

Right now I have:

    Dim conn As Data.SqlClient.SqlConnection = New Data.SqlClient.SqlConnection(WebConfigurationManager.ConnectionStrings("MyConnection").ToString())

    Dim ad As New SqlDataAdapter
    Dim selectSQL As String = "SELECT BookTitle, Publisher,  Location, CallNumber, [Extra_Description] AS Description, [ISBN] FROM [New_Book_Table] WHERE [Export_to_list]='True' AND [@Category]='True'"
    Dim selectCMD As SqlCommand = New SqlCommand(selectSQL, conn)
    ad.SelectCommand = selectCMD
    selectCMD.Parameters.Add("@Category", SqlDbType.NVarChar, 30).Value = getCategoryString()
    Dim ds As New DataSet

    ad.Fill(ds)
    ListView1.DataSource = ds
    ListView1.DataBind()

But get the error: System.Data.SqlClient.SqlException: Invalid column name '@Category'.

I guess because this isn't the correct way to do this. How can I do this? I can get the column name via query string. I want to pass in that column name into the query and have it be recognized as a column.

Answer 1

Well I figured this out, and it's a much easier method than trying to dynamically add parameters, since the initial SelectSQL is just a string, I dynamically constructed that string wit the following function:

Protected Function getSQLQuery() As String
    Dim baseQuery As String = "SELECT BookTitle, Publisher,  Location, CallNumber, [Extra_Description] AS Description, [ISBN] FROM [New_Book_Table] WHERE [Export_to_list]='True'"
    Dim category As String = getCategoryString()
    Return baseQuery & "AND [" & category & "]='True'"
End Function