Question

I’m getting the following error, ever since I moved my DataTable to a different function.

Both DataSource and DataSourceID are defined on 'TestView'.  Remove one definition.

By all means if you have tips on style / standards, I welcome that as well, I am very new to aspx coding. Any idea what could be causing this? It wasn’t happening before when it wasn’t its own function. Is it a local variable problem?

Here’s the code for the code that binds and is highlighted in the error:

testDAO tda = new testDAO();
DataTable testTable = new DataTable("TestView");
testTable = tda.GetTestTable();
TestView.DataSource = testTable;
TestView.DataBind();

Here’s the code for the GetTestTable():

public DataTable GetTestTable()
{
    DataTable testTable = new DataTable("TestView");
    testTable.Columns.Add("testdata", typeof(String));
    testTable.Columns.Add("user", typeof(String));
    testTable.Columns.Add("date", typeof(String));
    DataRow arow = testTable.NewRow();
    arow["testdata"] = "test data";
    arow["user"] = "System";
    arow["date"] = "";
    testTable.Rows.Add(arow);
    return testTable;
}

List view in aspx file:

<asp:ListView ID="TestView" runat="server">
                <ItemTemplate>
                    <tr id="row" runat="server" class='<%# Container.DataItemIndex % 2 == 0 ? "row" : "altrow" %>'>
                        <td align="left">
                            <%# Eval("testdata") %>
                        </td>
                        <td align="center">
                            <%# Eval("user") %>
                        </td>
                        <td align="center">
                            <%# Eval("date") %>
                        </td>
                    </tr>
                </ItemTemplate>
                <LayoutTemplate>
                    <table class="system">
                        <tr>
                            <th>
                                Test Data
                            </th>
                            <th>
                                User
                            </th>
                            <th>
                                Date
                            </th>
                        </tr>
                        <tr id="itemPlaceholder" runat="server" />
                    </table>
                </LayoutTemplate>
            </asp:ListView>

Answer 1

I think its due to some Naming conflicts Try renaming Either your DataTable name or ListView ID to somthing else like TestListView. Also you have an extra line for creating a New DataTable thats a redundency as you are assigning the table returned from method GetTestTable

Edit

If you are still having some problems then some where else you might be assigning a data source by setting DataSourceID to some data source provides, then do somthing like this:

TestView.DataSourceID = null;
testDAO tda = new testDAO();
DataTable testTable = tda.GetTestTable();
TestView.DataSource = testTable;
TestView.DataBind();

setting DataSourceID to null will definitely solve the problem..