ObjectDataSource找不到非泛型方法

I have this ASP.NET code:

我有一个ASP。NET代码:

<asp:DropDownList 
    ID="ddlBrokers" 
    runat="server" 
    AutoPostBack="true" 
    DataSourceID="srcBrokers" 
    DataTextField="broker" 
    DataValueField="brokerId"
/>

<asp:ObjectDataSource
    id="srcBrokers" 
    TypeName="DatabaseComponent.DBUtil" 
    SelectMethod="GetBrokers" 
    runat="server">
</asp:ObjectDataSource>
<a