【蛙蛙推荐】GridView和ObjectDataSource更新数据的一个Bug
相信大家在利用ObjectDataSource更新GridView或者FormView数据的时候一定遇到过这样的错误。
ObjectDataSource 'ods1' could not find a non-generic method 'ModifyPhrase' that has parameters: PID, pgid, content, Context.
你可以用google搜索一下这个错误，国内国外都有讨论，有人说这是微软的一个Bug。其实是因为GridView自动给数据源更新方法生成的参数不正确引起的。GridView在Updating事件里传递给DataSource的参数有DataKeyNames字段，以及你编辑状态下非readonly的字段，如果这几个字段加起来和数据源声明的几个参数对应起来，那么就会成功的调用数据源的更新方法，否则就会出现类似上面的错误。解决这个问题就是在Updating事件里处理传过去的参数。我做了一个例子。
这是数据源的代码
using System;using System.Collections.Generic;using System.ComponentModel;public class Entity
{
public Entity(int id, string name)
{
m_id = id; m_name = name;
} int m_id; public int Id { get { return m_id; } set { m_id = value; } } string m_name; public string Name { get { return m_name; } set { m_name = value; } }
}[DataObject]public class BLL{ static Dictionary<int, string> dict = new Dictionary<int, string>(); public BLL() { } [DataObjectMethod(DataObjectMethodType.Insert, true)] public void Add(int id, string name) { dict.Add(id, name); } [DataObjectMethod(DataObjectMethodType.Select, true)] public Entity[] GetAll() { Entity[] entities = new Entity[dict.Count]; int i = 0; foreach (KeyValuePair<int, string> kvp in dict) { entities[i] = new Entity(kvp.Key, kvp.Value); i++; } return entities; } [DataObjectMethod(DataObjectMethodType.Update, true)] public void Update(int pid, string pname) { dict[pid] = pname; } [DataObjectMethod(DataObjectMethodType.Delete, true)] public void Delete(int id) { dict.Remove(id); }}
这是页面的代码
<%@ Page Language="C#" Debug="true" Trace="true" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void LinkButton1_Click(object sender, EventArgs e) { int id; int.TryParse(txtID.Text, out id); new BLL().Add(id, txtName.Text); GridView1.DataBind(); } protected void ObjectDataSource1_Updating(object sender, ObjectDataSourceMethodEventArgs e) { //update方法本来有俩参数pid和name，而key是id，而修改的数据是datafeild是name //所以我们要转换一下，并把不用的参数去调，另外参数不区分大小写 e.InputParameters["pid"] = e.InputParameters["Id"]; e.InputParameters["pname"] = e.InputParameters["name"]; e.InputParameters.Remove("id"); e.InputParameters.Remove("name"); }</script><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server"> <title>测试GridView的编辑功能</title></head><body> <form id="form1" runat="server"> <div> <!--要想使用GridView的编辑功能，要设置DataKeyNames属性，并把主键字段设置成ReadOnly 字段声明这里一定要包含update方法需要的参数，然后在数据源的Updating事件里进行转换 否则有些参数无法赋值了 --> <asp:GridView ID="GridView1" runat="server" AllowPaging="True" DataSourceID="ObjectDataSource1" DataKeyNames="ID" AutoGenerateColumns="False"> <Columns> <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" /> <asp:BoundField DataField="ID" HeaderText="ID" ReadOnly="True" /> <asp:BoundField DataField="Name" HeaderText="Name" /> </Columns> <EmptyDataTemplate> 没有数据 </EmptyDataTemplate> </asp:GridView> <asp:ObjectDataSource ID="ObjectDataSource1" runat="server" DeleteMethod="Delete" InsertMethod="Add" SelectMethod="GetAll" TypeName="BLL" UpdateMethod="Update" OnUpdating="ObjectDataSource1_Updating" > <DeleteParameters> <asp:Parameter Name="id" Type="Int32" /> </DeleteParameters> <UpdateParameters> <asp:Parameter Name="pid" Type="Int32" /> <asp:Parameter Name="pname" Type="String" /> </UpdateParameters> <InsertParameters> <asp:Parameter Name="id" Type="Int32" /> <asp:Parameter Name="name" Type="String" /> </InsertParameters> </asp:ObjectDataSource> <br /> ID<asp:TextBox ID="txtID" runat="server"></asp:TextBox><br /> NAME<asp:TextBox ID="txtName" runat="server"></asp:TextBox><br /> <asp:LinkButton ID="LinkButton1" runat="server" OnClick="LinkButton1_Click">添加</asp:LinkButton></div> </form></body></html>
