ASP.Net使用EF网格视图删除按钮

Question

Asp.net使用Entity框架工作并在网格视图中按下删除按钮时删除该行，然后显示此项＆＃34;该对象无法删除，因为在ObjectStateManager中找不到该对象。＆＃34; ＆＃34; 这是ascx代码：

  <%@ Control Language="C#" AutoEventWireup="true" 
  CodeBehind="ctrl_ResearcherMyResearch.ascx.cs" 
  Inherits="ITI.GeoXera.ASP.User_Controls.ctrl_ResearcherMyResearch" %>

<asp:GridView ID="grd_Researcher" runat="server" AutoGenerateColumns="False" 
 DataKeyNames="Id,Title" DataSourceID="Researcher" 
 OnRowDeleting="grd_Researcher_RowDeleting"  
OnRowEditing="grd_Researcher_RowEditing" 
OnRowUpdating="grd_Researcher_RowUpdating" PageSize="3" Width="900px" 
AllowPaging="True" CellPadding="4" ForeColor="#333333" GridLines="None" 
HorizontalAlign="Center" >
<AlternatingRowStyle HorizontalAlign="Center" VerticalAlign="Middle" 
BackColor="White" />
<Columns>
    <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="True" 
SortExpression="Id" >
    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
    </asp:BoundField>
    <asp:BoundField DataField="Title" HeaderText="Title" 
SortExpression="Title" >
    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
    </asp:BoundField>
    <asp:BoundField DataField="Author" HeaderText="Author" 
SortExpression="Author" >
    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
    </asp:BoundField>
    <asp:BoundField DataField="Description" HeaderText="Description" 
SortExpression="Description" >
    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
    </asp:BoundField>
    <asp:BoundField DataField="LatitudeFrom" HeaderText="Lat" 
SortExpression="LatitudeFrom" >
    <HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" />
    </asp:BoundField>

    <asp:BoundField DataField="LongitudeFrom" HeaderText="Long" 
SortExpression="LongitudeFrom" />

    <asp:BoundField DataField="FkUser" HeaderText="FkUser" 
SortExpression="FkUser" Visible="False" ReadOnly="True" />
    <asp:BoundField DataField="Link" HeaderText="Link" SortExpression="Link" 
/>
    <asp:CommandField ButtonType="Button" DeleteText="" InsertText="" 
NewText="" SelectText="" ShowEditButton="True" />
    <asp:CommandField ButtonType="Button" InsertText="" NewText="" 
SelectText="" ShowDeleteButton="True" />
</Columns>
<EditRowStyle HorizontalAlign="Center" VerticalAlign="Middle" Height="30px" 
BackColor="#2461BF" Width="20px" Wrap="True" />
<EmptyDataRowStyle HorizontalAlign="Center" VerticalAlign="Middle" />
<FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<HeaderStyle HorizontalAlign="Center" VerticalAlign="Middle" Height="30px" 
BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<PagerSettings PageButtonCount="5" />
<PagerStyle VerticalAlign="Middle" BackColor="#2461BF" ForeColor="White" 
HorizontalAlign="Center" />
<RowStyle HorizontalAlign="Center" VerticalAlign="Middle" 
BackColor="#EFF3FB" Font-Strikeout="False" Width="50px" />
<SelectedRowStyle HorizontalAlign="Center" VerticalAlign="Middle" 
BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
<SortedAscendingCellStyle BackColor="#F5F7FB" />
<SortedAscendingHeaderStyle BackColor="#6D95E1" />
<SortedDescendingCellStyle BackColor="#E9EBEF" />
<SortedDescendingHeaderStyle BackColor="#4870BE" />
</asp:GridView>
<asp:ObjectDataSource ID="Researcher" runat="server" 
DataObjectTypeName="ITI.GeoXera.Model.Models.Research" DeleteMethod="Delete" 
InsertMethod="Add" SelectMethod="GetAllBind" 
TypeName="ITI.GeoXera.Data.Repositories.ResearchRepository" 
UpdateMethod="Update"></asp:ObjectDataSource>

<p>
&nbsp;</p>

<div class="box box-info">
<asp:Panel ID="Panel1" runat="server" GroupingText=" Research Information">

<div class="box-body">

    <div class="form-group">
        <asp:Label CssClass="col-sm-2 control-label" ID="lbl_Title" 
runat="server" Text="Title"></asp:Label>
        <div class="col-sm-10">
            <asp:TextBox CssClass="form-control" ID="txt_Title" 
runat="server" AutoCompleteType="Disabled"></asp:TextBox>
            <asp:RequiredFieldValidator ID="vldreq_Title" runat="server" 
ControlToValidate="txt_Title" ForeColor="#CC0000" ToolTip="Please Enter 
Research Title">*</asp:RequiredFieldValidator>
         </div>
        </div>

            <div class="form-group">
        <asp:Label ID="lbl_Author" runat="server" CssClass="col-sm-2 
control-label" Text="Author"></asp:Label>
        <div class="col-sm-10">
            <asp:TextBox ID="txt_Author" runat="server" 
AutoCompleteType="Disabled" CssClass="form-control" ></asp:TextBox>
            <asp:RequiredFieldValidator ID="vldreq_Author" runat="server" 
ErrorMessage="*" ForeColor="#CC0000" ToolTip="Please Enter Author Name" 
ControlToValidate="txt_Author"></asp:RequiredFieldValidator>
        </div>
    </div>


    <div class="form-group">
        <asp:Label ID="lbl_Description" runat="server" CssClass="col-sm-2 
control-label" Text="Description"></asp:Label>
        <div class="col-sm-10">
            <asp:TextBox ID="txt_Description" runat="server" 
AutoCompleteType="Disabled" CssClass="form-control" ></asp:TextBox>
            <asp:RequiredFieldValidator ID="vldreq_Description" 
runat="server" ErrorMessage="*" ForeColor="#CC0000" ToolTip="Please Enter 
Description" ControlToValidate="txt_Description">
</asp:RequiredFieldValidator>
        </div>
    </div>

    <div class="form-group">
        <asp:Label CssClass="col-sm-2 control-label" ID="lbl_LatitudeFrom" 
runat="server" Text="Latitude From"></asp:Label>
        <div class="col-sm-4">
            <asp:TextBox CssClass="form-control" ID="txt_LatitudeFrom" 
runat="server" AutoCompleteType="Disabled"></asp:TextBox>
            <asp:RequiredFieldValidator ID="vlrLatFrom" runat="server" 
ControlToValidate="txt_LatitudeFrom" ForeColor="#FF3300" ToolTip="Please 
Enter 
Required Data">*</asp:RequiredFieldValidator>
        </div>

        <asp:Label CssClass="col-sm-2 control-label" ID="lbl_LatitudeTo" 
runat="server" Text="Latitude To"></asp:Label>
        <div class="col-sm-4">
            <asp:TextBox CssClass="form-control" ID="txt_LatitudeTo" 
runat="server" AutoCompleteType="Disabled"></asp:TextBox>
            <asp:RequiredFieldValidator ID="vlrLatTo" runat="server" 
ControlToValidate="txt_LatitudeTo" ForeColor="#FF3300" ToolTip="Please Enter 
Required Data">*</asp:RequiredFieldValidator>
        </div>
    </div>

     <div class="form-group">
        <asp:Label CssClass="col-sm-2 control-label" ID="lbl_LongitudeFrom" 
runat="server" Text="Longitude From"></asp:Label>
        <div class="col-sm-4">
            <asp:TextBox CssClass="form-control" ID="txt_LongitudeFrom" 
runat="server" AutoCompleteType="Disabled"></asp:TextBox>
            <asp:RequiredFieldValidator ID="vlrLongFrom" runat="server" 
ControlToValidate="txt_LongitudeFrom" ForeColor="#FF3300" ToolTip="Please 
Enter 
Required Data">*</asp:RequiredFieldValidator>
        </div>

        <asp:Label CssClass="col-sm-2 control-label" ID="lbl_LongitudeTo" 
runat="server" Text="Longitude To"></asp:Label>
        <div class="col-sm-4">
            <asp:TextBox CssClass="form-control" ID="txt_LongitudeTo" 
runat="server" AutoCompleteType="Disabled"></asp:TextBox>
            <asp:RequiredFieldValidator ID="vlrLongTo" runat="server" 
ControlToValidate="txt_LongitudeTo" ForeColor="#FF3300" ToolTip="Please 
Enter Required Data">*</asp:RequiredFieldValidator>
        </div>
    </div>
             <div class="form-group">
        <asp:Label CssClass="col-sm-2 control-label" ID="lbl_Link" 
runat="server" Text="Link"></asp:Label>
        <div class="col-sm-10">
            <asp:TextBox CssClass="form-control" ID="txt_Link" 
runat="server" AutoCompleteType="Disabled"></asp:TextBox>
            <asp:RequiredFieldValidator ID="RequiredFieldValidator1" 
runat="server" ControlToValidate="txt_Link" ForeColor="#FF3300" 
ToolTip="Please Enter Link Path">*</asp:RequiredFieldValidator>
        </div>
    </div>
</div>
<div class="box-footer">
    <asp:Button CssClass="btn btn-info pull-right" ID="btn_SaveInfo"  
runat="server" Text="Save" OnClick="btn_SaveInfo_OnClick" />
</div>

    

ascx.cs代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Windows.Forms;
using ITI.GeoXera.Data.InfraStructure;
using ITI.GeoXera.Data.Repositories;
using ITI.GeoXera.Model.Models;

 namespace ITI.GeoXera.ASP.User_Controls
{
public partial class ctrl_ResearcherMyResearch : System.Web.UI.UserControl
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            //grd_Researcher.DataBind();
        }
    }

    protected void grd_Researcher_RowUpdating(object sender, 
     GridViewUpdateEventArgs e)
    {

        using (UnitOfWork uof = new UnitOfWork())
        {
            int index = e.RowIndex;
            Research research = new Research();
            User user = new User();
            research.Id = Convert.ToInt32(grd_Researcher.DataKeys[index]
               ["Id"]);
            research.Title = e.NewValues["Title"].ToString();
            research.Description = e.NewValues["Description"].ToString();
            research.Author = e.NewValues["Author"].ToString();
            research.LatitudeFrom = 
            Convert.ToDouble(e.NewValues["LatitudeFrom"]);
            research.LatitudeTo = 
            Convert.ToDouble(e.NewValues["LatitudeTo"]);
            research.LongitudeFrom = 
            Convert.ToDouble(e.NewValues["LongitudeFrom"]);
            research.LongitudeTo = 
           Convert.ToDouble(e.NewValues["LongitudeTo"]);
            research.Link = e.NewValues["Link"].ToString();
            research.FkUser = 1;
            uof.ResearchRepository.Update(research);
            grd_Researcher.EditIndex = -1;
            grd_Researcher.DataBind();
            uof.Commit();
        }

    }

    protected void grd_Researcher_RowEditing(object sender, 
          GridViewEditEventArgs e)
    {
        using (UnitOfWork uof = new UnitOfWork())
        {
            grd_Researcher.EditIndex = e.NewEditIndex;
            grd_Researcher.DataBind();

        }
    }

    protected void grd_Researcher_RowDeleting(object sender, 
        GridViewDeleteEventArgs e)
    {
        string Title = 
            Convert.ToString(grd_Researcher.DataKeys[e.RowIndex].Values[1]);
        using (UnitOfWork uof = new UnitOfWork())
        {
            if (Title != null || Title != "")
            {
                Research research = 
          uof.ResearchRepository.GetAll().Where(res => res.Title == 
           Title).FirstOrDefault();
                if (research != null)
                {
                    uof.ResearchRepository.Delete(research);
                    uof.Commit();
                    //grd_Researcher.DataSource = 
               uof.ResearchRepository.GetAllBind();
                    MessageBox.Show("Deleted successfully.");
                }
                else
                {

                    MessageBox.Show("Not Found");

                }
            }
               grd_Researcher.EditIndex = -1;
               grd_Researcher.DataBind();
        }
    }

    protected void btn_SaveInfo_OnClick(object sender, EventArgs e)
    {
        using (UnitOfWork uof = new UnitOfWork())
        {
            User u = new User();
            bool entryFound = false;
            Research research = new Research();
            foreach (GridViewRow row in grd_Researcher.Rows)
            {
                object val1 = row.Cells[1].Text;

                if (val1 != null && val1.ToString() == txt_Title.Text)
                {
                    MessageBox.Show("Entry already exist");
                    entryFound = true;
                    break;
                }
            }
            if (!entryFound)
            {
                research.Title = txt_Title.Text;
                research.Author = txt_Author.Text;
                research.Description = txt_Description.Text;
                research.LatitudeFrom = 
    Convert.ToDouble(txt_LatitudeFrom.Text);
                research.LatitudeTo = Convert.ToDouble(txt_LatitudeTo.Text);
                research.LongitudeFrom = 
      Convert.ToDouble(txt_LongitudeFrom.Text);
                research.LongitudeTo = 
      Convert.ToDouble(txt_LongitudeTo.Text);
                research.Link = txt_Link.Text;
                research.FkUser = Convert.ToInt32(Session["UserID"]);
                uof.ResearchRepository.Add(research);
                grd_Researcher.DataBind();
                uof.Commit();

                MessageBox.Show("Data Added");
                foreach (var control in this.Controls)
                {
                    System.Web.UI.WebControls.TextBox tb = control as 
     System.Web.UI.WebControls.TextBox;
                    if (tb != null)
                    {
                        tb.Text = string.Empty;
                    }
                }
                uof.ResearchRepository.GetAllBind();
            }
        }
    }

}

}

提前致谢

Answer 1

您确定要删除的行在＆＃34;标题＆＃34;中有值。您使用if (Title != null || Title != "")发布的代码存在允许null和空值的错误。如果你想阻止它，它应该是if (Title != null && Title != "")。