InvalidOperationException: ObjectDataSource could not find a non-generic method that has parameters:

Question

I'm trying to code an ObjectDataSource for a local ASP.NET page.

Reading the Help files on MSDN always leave me scratching my head, wondering what exactly they might be implying. For example, I am not sure what my TypeName should be (though that link has an interesting example).

Once I get the basics to work, I will venture into deeper waters.

The first line of my *.aspx file contains my definitions:

<%@ Page Title="Reporter" Language="C#" MasterPageFile="~/local.Master"
    AutoEventWireup="true" CodeBehind="Reporter.aspx.cs"
    Inherits="AcpServiceNS.Reporter" %>

In this page, I have TextBox controls named txtStartDate and txtEndDate and a number of DropDownList controls named ddlStartTime, ddlEndTime, ddlAction, ddlFilter1, and ddlFilter2.

I also have the following ObjectDataSource:

<asp:ObjectDataSource ID="dsReport" runat="server"
     SelectMethod="GetData"
     TypeName="System.Data.DataTable"
     ConvertNullToDBNull="True" >
  <SelectParameters>
    <asp:ControlParameter ControlID="txtStartDate" Name="startDate" PropertyName="Text" Type="String" DefaultValue="" />
    <asp:ControlParameter ControlID="ddlStartTime" Name="startTime" PropertyName="Text" Type="String" DefaultValue="" />
    <asp:ControlParameter ControlID="txtEndDate" Name="endDate" PropertyName="Text" Type="String" DefaultValue="" />
    <asp:ControlParameter ControlID="ddlEndTime" Name="endTime" PropertyName="Text" Type="String" DefaultValue="" />
    <asp:ControlParameter ControlID="ddlAction" Name="action1" PropertyName="Text" Type="String" DefaultValue="" />
    <asp:ControlParameter ControlID="ddlFilter1" Name="filter1" PropertyName="Text" Type="String" DefaultValue="" />
    <asp:ControlParameter ControlID="ddlFilter2" Name="filter2" PropertyName="Text" Type="String" DefaultValue="" />
  </SelectParameters>
</asp:ObjectDataSource>

A GridView control is going to be on the *.aspx page, and will be used to display the data:

<asp:GridView ID="gvReport" AllowSorting="true" AutoGenerateColumns="false" AllowPaging="true" Font-Size="Small" PageSize="30" Width="100%"
  OnRowDataBound="Report_RowDataBound"
  OnRowCommand="Report_RowCommand"
  DataKeyNames="Op_ID,Serial_Number,Date_Time,Test_Result"
  DataSourceID="dsReport"
  runat="server">
  <Columns>
    <asp:TemplateField HeaderText="Op_ID" HeaderStyle-Width="20%">
      <ItemTemplate>
        <asp:LinkButton ID="lbOp_ID" runat="server" CommandArgument='<%# Container.DataItemIndex %>' CommandName="Op_ID" />
      </ItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="Serial_Number" HeaderStyle-Width="20%">
      <ItemTemplate>
        <asp:LinkButton ID="lbSerial_Number" runat="server" CommandArgument='<%# Container.DataItemIndex %>' CommandName="Serial_Number" />
      </ItemTemplate>
    </asp:TemplateField>
    <asp:BoundField DataField="Date_Time" HeaderText="Date_Time" SortExpression="Date_Time" HeaderStyle-Width="20%" />
    <asp:BoundField DataField="Test_Result" HeaderText="Test_Result" SortExpression="Test_Result" HeaderStyle-Width="40%" />
  </Columns>
</asp:GridView>

To get this to load an empty dataset, I have created this simple stub in my codebehind:

namespace AcpServiceNS {

  public partial class Reporter : System.Web.UI.Page {

    protected void Page_Load(object sender, EventArgs e) {
    }

    [DataObjectMethod(DataObjectMethodType.Select)]
    protected static DataTable GetData(string startDate, string startTime, string endDate, string endTime,
      string action1, string filter1, string filter2) {
      var table = new DataTable();
      table.Columns.Add("Op_ID", typeof(string));
      table.Columns.Add("Serial_Number", typeof(string));
      table.Columns.Add("Date_Time", typeof(DateTime));
      table.Columns.Add("Test_Result", typeof(string));
      return table;
    }

  }

}

Yes! All that is above is basically a Table Definition, but it should be enough to start my *.aspx page.

When I try to run this, I get the following Exception:

System.InvalidOperationException: ObjectDataSource 'dsReport' could not find a non-generic method 'GetData' that has parameters: startDate, startTime, endDate, endTime, action1, filter1, filter2.

It appears that I have spelled and cased all of the parameters correctly, so what have I done wrong? Is TypeName used incorrectly?

Answer 1

From the ObjectDataSource, I would say yes you're using TypeName wrong. In the MSDN article, it refers to the class which hosts the method, not the return type of the method.

Try changing TypeName="System.Data.DataTable" to TypeName="AcpServiceNS.Reporter"