'ObjectDataSource1'在asp.net中找不到非泛型方法

Question

我正在使用GridView来显示和编辑数据，但是当我点击GridView左侧的更新时，我收到一条错误消息：

ObjectDataSource'ObjectDataSource1'找不到具有参数的非泛型方法'updateEmployee'：old_EmployeeID，old_EmployeeName，old_DepartmentID， EmployeeName ，DepartmentID，EmployeeID。

请参阅下面的网页代码：

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
    BackColor="#DEBA84" BorderColor="#DEBA84" BorderStyle="None" BorderWidth="1px" 
    CellPadding="3" CellSpacing="2" DataSourceID="ObjectDataSource1" DataKeyNames="EmployeeID">
    <Columns>
    <asp:CommandField ShowEditButton="True" />
    <asp:BoundField DataField="EmployeeID" HeaderText="EmployeeID" 
        SortExpression="EmployeeID" />
    <asp:BoundField DataField="EmployeeName" HeaderText="EmployeeName" 
        SortExpression="EmployeeName" />
    <asp:TemplateField HeaderText="DepartmentID" SortExpression="DepartmentID">
        <EditItemTemplate>
        <asp:DropDownList ID="DropDownList1" runat="server" 
            SelectedValue='<%# Bind("DepartmentID") %>'>
            <asp:ListItem>Select Department</asp:ListItem>
            <asp:ListItem Value="1">SM</asp:ListItem>
            <asp:ListItem Value="2">CDS</asp:ListItem>
            <asp:ListItem Value="3">AM</asp:ListItem>
            <asp:ListItem Value="4">FS</asp:ListItem>
        </asp:DropDownList>
        </EditItemTemplate>
        <ItemTemplate>
        <asp:Label ID="Label1" runat="server" Text='<%# Bind("DepartmentID") %>'></asp:Label>
        </ItemTemplate>
    </asp:TemplateField>
    </Columns>
</asp:GridView>
<br />
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" 
    SelectMethod="getAllEmployees" 
    TypeName="WebApplication1.Learning.Updating.TblEmployeeDataAccessLayer" 
    UpdateMethod="updateEmployee" ConflictDetection="CompareAllValues" OldValuesParameterFormatString="old_{0}">
    <UpdateParameters>
    <asp:Parameter Name="old_EmployeeID" Type="Int32" />
    <asp:Parameter Name="old_EmployeeName" Type="String" />
    <asp:Parameter Name="old_DepartmentID" Type="Int32" />
    <asp:Parameter Name="EmployeeName" Type="String" />
    <asp:Parameter Name="DepartmentID" Type="Int32" />
    </UpdateParameters>
</asp:ObjectDataSource>    

然后请参阅我的数据访问类和方法：

public class Employee
{
    public int EmployeeID { get; set; }
    public string EmployeeName { get; set; }
    public int DepartmentID { get; set; }
}    

public class TblEmployeeDataAccessLayer
{
    public static List<Employee> getAllEmployees()
    {
        List<Employee> employees = new List<Employee>();
        String sqlStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        using (OracleConnection ocon = new OracleConnection(sqlStr))
        {
            OracleCommand ocmd = new OracleCommand("select * from tblemployee", ocon);
            ocmd.Connection.Open();
            OracleDataReader rdr = ocmd.ExecuteReader();
            while (rdr.Read())
            {
                Employee employee = new Employee();
                employee.EmployeeID = Convert.ToInt32(rdr["EMPLOYEEID"]);
                employee.EmployeeName = rdr["NAME"].ToString();
                employee.DepartmentID = Convert.ToInt32(rdr["DEPTID"]);
                employees.Add(employee);
            }
        }
        return employees;
    }

    public static void updateEmployee(int old_EmployeeID, string old_EmployeeName, int old_DepartmentID,
        string EmployeeName, int DepartmentID)
    {
        string sqlCon = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        StringBuilder sb = new StringBuilder();
        sb.Append("update tblemployee set name = :name, deptid = :deptid where employeeid = :empid ");
        sb.Append(" and name = :old_name and deptid = :old_deptid");
        using (OracleConnection ocon = new OracleConnection(sqlCon))
        {
            OracleCommand ocmd = new OracleCommand(sb.ToString(), ocon);
            ocmd.Parameters.Add(":name", EmployeeName);
            ocmd.Parameters.Add(":deptid", DepartmentID);
            ocmd.Parameters.Add(":empid", old_EmployeeID);
            ocmd.Parameters.Add(":old_name", old_EmployeeName);
            ocmd.Parameters.Add(":old_deptid", old_DepartmentID);

            ocmd.Connection.Open();
            ocmd.ExecuteNonQuery();
        }
    }
}    

所以，显然在updateEmployee方法中只有5个参数，但我感到困惑的是，错误消息说找不到具有参数的非泛型方法'updateEmployee'：

old_EmployeeID，old_EmployeeName，old_DepartmentID， EmployeeName ，DepartmentID，EmployeeID

似乎它试图寻找有6个参数的方法，为什么？任何人都可以告诉我原因吗？