GridView binding with custom property in EntityObject derived class fails in ASP.NET

Question

I've an Entity Framework Layer and I've extended a class from that layer. The code is as follows:

public partial class FeatureMaster : EntityObject
{
    public string ParentFeatureName
    {
        get
        {
            return (from r in Global.dc.FeatureMasters
                    where r.FeatureId == FeatureParentId
                    select r).SingleOrDefault().FeatureName;
        }
        set
        {
            FeatureParentId = (from r in Global.dc.FeatureMasters
                               where r.FeatureName == value
                               select r).SingleOrDefault().FeatureId;
            ReportPropertyChanged(("ParentFeatureName"));
            ReportPropertyChanged(("FeatureParentId"));
        }
    }
}

Now I wish to use the same in my ASP.NET Page. The code for my ASP.NET Page is:

    <%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true"
    CodeBehind="ListFeatureMaster.aspx.cs" Inherits="Backend.ListFeatureMaster" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="cpMain" runat="server">
    <asp:GridView ID="grdRecords" runat="server" AllowPaging="True" AllowSorting="True"
        AutoGenerateColumns="False" DataKeyNames="FeatureId" DataSourceID="EntityDataSource1">
        <Columns>
            <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" />
            <asp:BoundField DataField="FeatureId" HeaderText="FeatureId" ReadOnly="True" SortExpression="FeatureId" />
            <asp:BoundField DataField="FeatureName" HeaderText="FeatureName" SortExpression="FeatureName" />
            <asp:BoundField DataField="FeatureParentId" HeaderText="FeatureParentId" SortExpression="FeatureParentId" />
            <asp:BoundField DataField="FeatureDescription" HeaderText="FeatureDescription" SortExpression="FeatureDescription" />
            <asp:TemplateField HeaderText="ParentFeatureName" SortExpression="ParentFeatureName">
                <EditItemTemplate>
                    <asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="EntityDataSource1"
                        AppendDataBoundItems="true" DataTextField="ParentFeatureName" DataValueField="ParentFeatureName"
                        SelectedValue='<%# Bind("ParentFeatureName") %>'>
                    </asp:DropDownList>
                </EditItemTemplate>
                <ItemTemplate>
                    <asp:Label ID="Label1" runat="server" Text='<%# Eval("ParentFeatureName") %>'></asp:Label>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>
    <asp:EntityDataSource ID="EntityDataSource1" runat="server" ConnectionString="name=BackendEntities"
        DefaultContainerName="BackendEntities" EnableFlattening="False" EntitySetName="FeatureMasters"
        EntityTypeFilter="FeatureMaster" EnableDelete="True" EnableUpdate="True">
    </asp:EntityDataSource>
        <asp:EntityDataSource ID="EntityDataSource2" runat="server" ConnectionString="name=BackendEntities"
        DefaultContainerName="BackendEntities" EnableFlattening="False" EntitySetName="FeatureMasters"
        EntityTypeFilter="FeatureMaster" EnableDelete="True" EnableUpdate="True">
    </asp:EntityDataSource>
</asp:Content>

The trouble is that when I execute this code, it works well on first load and navigation, but when I try to update the record, I get the error. Please help me to resolve the same.

Error message says:

A property named 'ParentFeatureName' was not found on the entity during an insert, update, or delete operation. Check to ensure that properties specified as binding expressions are available to the data source.

Community · Accepted Answer · 2017-05-23 11:50:16Z

1

I think the problem is that you don't attach a custom property to your entity, and then save it. You can have a look Adding customer property to entity class

Hope it helps.

edited May 23, 2017 at 11:50

CommunityBot

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answered Apr 19, 2013 at 13:15

cat916

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1 Comment

Sanket Tarun Shah Over a year ago

@minhchat_vo - its not working and not helping me. Please suggest me some other alternative.

Sanket Tarun Shah · Accepted Answer · 2013-04-21 10:18:07Z

I got the solution.

I changed definition of GridView and added OnRowUpdating event to that. The ASPX Page code now looks like:

<asp:GridView ID="grdRecords" runat="server" AllowPaging="True" AllowSorting="True"
    AutoGenerateColumns="False" DataKeyNames="FeatureId" DataSourceID="EntityDataSource1" OnRowUpdating="grdRecords_RowUpdating">

In my .aspx.cs file, I added code for Event Handler. The code for the same looks as below:

        protected void grdRecords_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        int primaryKey = Convert.ToInt32(grdRecords.DataKeys[e.RowIndex].Value);

        FeatureMaster existingRecord = Global.dc.FeatureMasters.First(r => r.FeatureId == primaryKey);
        existingRecord.FeatureName = e.NewValues["FeatureName"].ToString();
        existingRecord.ParentFeatureName = ((DropDownList)(grdRecords.Rows[e.RowIndex].FindControl("DropDownList1"))).SelectedValue.ToString();
        existingRecord.FeatureDescription = e.NewValues["FeatureDescription"].ToString();

        Global.dc.SaveChanges();

        grdRecords.EditIndex = -1;

        e.Cancel = true;
    }

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