一个很有深度的Gridview问题，大家都来讨论一下！

我在用ScriptManager的时候也遇到了这样怪异的错误信息？？哪位能解释下

情况是这样的
Employee.cs   using System;public class Employee
{
    public Employee() { }    private int _id;
    public int Id
    {
        get { return _id; }
        set { _id = value; }
    }    private string _employeename;
    public string EmployeeName
    {
        get { return _employeename; }
        set { _employeename = value; }
    }    private bool _sex;
    public bool Sex
    {
        get { return _sex; }
        set { _sex = value; }
    }    private string _employeecode;
    public string EmplyeeCode
    {
        get { return _employeecode; }
        set { _employeecode = value; }
    }    private int _department;
    public int Department
    {
        get { return _department; }
        set { _department = value; }
    }    private string _employeepassword;
    public string EmployeePassword
    {
        get { return _employeepassword; }
        set { _employeepassword = value; }
    }    private bool _employeestate;
    public bool EmployeeState
    {
        get { return _employeestate; }
        set { _employeestate = value; }
    }    private string _re;
    public string Re
    {
        get { return _re; }
        set { _re = value; }
    }    private int _turn;
    public int Turn
    {
        get { return _turn; }
        set { _turn = value; }
    }    public Employee(int id, string employeeName, bool sex, string employeeCode, int department, string employeePassword, bool employeeState, string re, int turn)
    {
        this.Id = id;
        this.EmployeeName = employeeName;
        this.Sex = sex;
        this.EmplyeeCode = employeeCode;
        this.Department = department;
        this.EmployeePassword = employeePassword;
        this.EmployeeState = employeeState;
        this.Re = re;
        this.Turn = turn;
    }
EmployeeBLLusing System;
using System.Data;
using System.Collections.Generic;[System.ComponentModel.DataObject]
public class EmployeeBLL
{
    public EmployeeBLL() { }    public List<Employee> GetEmployee(bool orderType,int department,int employeeState)
    {
        List<Employee> employees = new List<Employee>();
        string strWhere = string.Empty;
        if (employeeState != -1)
        {
            strWhere = "EmployeeState=" + employeeState.ToString();
        }        if (department != 0)
        {
            if (string.IsNullOrEmpty(strWhere))
                strWhere = "Department=" + department.ToString();
            else
                strWhere += " AND Department=" + department.ToString();
        }
        DataSet dataSet = CommonDAL.PageInationDataSet("Employee", "*", "Turn", 0, 0, orderType, strWhere);
        foreach (DataRow dataRow in dataSet.Tables[0].Rows)
        {
            Employee employee = new Employee();
            employee.Id = Convert.ToInt32(dataRow["Id"]);
            employee.EmployeeName = Convert.ToString(dataRow["EmployeeName"]);
            employee.Sex = Convert.ToBoolean(dataRow["Sex"]);
            employee.EmplyeeCode = Convert.ToString(dataRow["EmployeeCode"]);
            employee.Department = Convert.ToInt32(dataRow["Department"]);
            employee.EmployeePassword = Convert.ToString(dataRow["EmployeePassword"]);
            employee.EmployeeState = Convert.ToBoolean(dataRow["EmployeeState"]);
            employee.Re = Convert.ToString(dataRow["Re"]);
            employee.Turn = Convert.ToInt32(dataRow["Turn"]);
            employees.Add(employee);
        }
        return employees;
    }
}
Employee.aspx<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="test.aspx.cs" Inherits="XinYun_RadControls.test" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="ObjectDataSource1"
            OnRowDataBound="GridView1_RowDataBound">        </asp:GridView>

    </div>
        <asp:ObjectDataSource ID="ObjectDataSource1" runat="server" OldValuesParameterFormatString="original_{0}" SelectMethod="GetEmployee" TypeName="EmployeeBLL">
                <SelectParameters>
                    <asp:Parameter DefaultValue="True" Name="orderType" Type="Boolean" />
                    <asp:Parameter DefaultValue="0" Name="department" Type="Int32" />
                    <asp:Parameter DefaultValue="-1" Name="employeeState" Type="Int32" />
                </SelectParameters>
        </asp:ObjectDataSource>
    </form>
</body>
</html>
        protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                if (e.Row.DataItem != null)
                {
                    Employee employee = (Employee)e.Row.DataItem;
                }
            }
        }
红色部分执行不过去

是Employee类型出现报错信息是无法将类型为“Employee”的对象强制转换为类型“Employee”。
============
类型不对.
错误报的很明显

但不用objectdatasource的时候，手动绑定
EmployeeBLL bll = new EmployeeBLL();
gridview1.datasource = bll.GetEmployee();
gridview1.databind()；
这就没问题

用三层不建议用objectdatasource，虽然被很多大侠痛批。再申明一下，偶的小小经验是带来的方便远不如带来的问题头疼～。

无法将类型为“Employee”的对象强制转换为类型“Employee”？
难道这两个不是同一个类？建议改另外一个类名试试。

Employee employee = (Employee)e.Row.DataItem;
=======
你看一下DataItem是什么.设个断点调试一下.

是够头疼的，明明跟踪到这是个Employee类型，就是不能用啊，难道还是要用DataBinder.Eval?

我试过了，用response.write(e.Row.DataItem)还是Employee

难者不会，会者不难。主要是你不知道如何调试。你至少可以在断点下在即时窗口（或者监视窗口）打印    ?e.Row.DataItem.GetType().FullName
   ?e.Row.DataItem.GetType().Assembly.FullName
   ?typeof(Employee).FullName
   ?typeof(Employee).Assembly.FullName嘛！如果要求证你到底有些什么类型，当然要如此打印，不能全凭嘴说。查找bug肯定要动手，而不是仅凭大脑分析。

调试，应该使用debug中断。使用那种打印，费时费力而且你做不了多少调试动作。

刚转到.net不久，不会调试啊，有谁试过了吗？的确是Employee类型啊

dataitem在强制转换类型时出错。你该这么做，把每个row中的值取出来。然后用employee类的new方法去把每个值再放进去。就不会出现问题了。

这位大哥能不能解释为什么用手动绑定可以，用ObjectDataSource数据源为什么不行呢？

设断点,F10,F11,F5按一变就知道做什么用的了。

是否是因为操作的源对象不同呢？页面上直接ObjectDataSourc绑定，是否你绑定的源与构造的类型不一样？～～～没碰过，睡先，明天再来看看

e.Row.DataItem 强制转换类型肯定会出问题的。建议：Employee employee = new Employee()
employee.Add(e.Row.DataItem);

是不是同一个Employee?注意一下命名空间

Employee是个实体类，不是IList,
照你的思路应该是
List<Employee> employees = new List<Employee>();
employees.Add(e.Row.DataItem);
这还是不行，现在用手动绑定没有问题，不能用ObjectDataSource,有点郁闷的说。

现在调试了一下，
e.Row.DataItem.GetType().Assembly.FullName >>> App_Code.rub9ym4b, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null
?typeof(Employee).Assembly.FullName >>> XinYun_RadControls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
是何原因？

我估计在你的整个解决方案里面有两个Employee这样的classsEmployee employee = (Employee)e.Row.DataItem;e.row.dataitem的employee的合名（命名空间＋类名）与当前所有的命名空间下面的Employee不相符。建议你把这样写断点到e.row.dateitem的时候，看一下它的类型。

我把Employee.cs是放在App_Code\TB\下的
断点我设了
?e.Row.DataItem.GetType().FullName和？typeof(Employee).FullName都是Employee
e.Row.DataItem.GetType().Assembly.FullName 是 App_Code.rub9ym4b, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null
?typeof(Employee).Assembly.FullName 是 XinYun_RadControls, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null
估计就是这原因，就是不知道怎么解决。把Employee.cs放在app_code外？

你用项目的类的全名
比如你的逻辑层的命名空间是：
更方便的方法是你到逻辑层里面看你的Employee.cs文件，有一行namespace
现在假如是namesapce BusuinessBusiness.Employee employee = (Business.Employee)e.Row.DataItem;

调试易

一个很有深度的Gridview问题，大家都来讨论一下！

解决方案 »