How do I update an entity object in GridView - asp.net

Question

I am using Entity Framework with ASPX webform. In my GridView(GV) I make all my columns with ItemTemplates and EditTemplates. When in edit mode I can select a new value, but it does not update the record. In the GV I have a DropDownList which is set to a EntityDataSource that matches it's related table for that field. What steps do I need, what events do I need to handle? I have tried the RowEditing and RowUpdating events, but have no useful code thus far. If you want me to show you some bad code - just ask and I will be more than happy too. I just need some guidance on wiring this up.

Answer 1

Assuming I have an ADO.NET entity data model called - customerEntities which has one table Customers with 3 columns:
CustomerId
Name
Surname
ASPX:
<asp:GridView ID="gvCustomers" runat="server" AutoGenerateEditButton="true"
AutoGenerateColumns="false" onrowcancelingedit="gvCustomers_RowCancelingEdit"
onrowediting="gvCustomers_RowEditing" onrowupdating="gvCustomers_RowUpdating" DataKeyNames="CustomerId">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:Label ID="lblId" runat="server" Text='<%# Bind("CustomerId") %>' />
<asp:Label ID="lblName" runat="server" Text='<%# Bind("Name") %>' />
<asp:Label ID="lblSurname" runat="server" Text='<%# Bind("Surname") %>' />
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txtName" runat="server" Text='<%# Bind("Name") %>' />
<asp:TextBox ID="txtSurname" runat="server" Text='<%# Bind("Surname") %>' />
</EditItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Code behind:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
BindCustomers();
}
private void BindCustomers()
{
customerEntities entityModel = new customerEntities();
gvCustomers.DataSource = entityModel.Customers;
gvCustomers.DataBind();
}
protected void gvCustomers_RowEditing(object sender, GridViewEditEventArgs e)
{
gvCustomers.EditIndex = e.NewEditIndex;
BindCustomers();
}
protected void gvCustomers_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
gvCustomers.EditIndex = -1;
BindCustomers();
}
protected void gvCustomers_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
int customerId = (int)gvCustomers.DataKeys[e.RowIndex].Value;
TextBox txtName = (TextBox)gvCustomers.Rows[e.RowIndex].FindControl("txtName");
TextBox txtSurname = (TextBox)gvCustomers.Rows[e.RowIndex].FindControl("txtSurname");
customerEntities entityModel = new customerEntities();
Customer customer = entityModel.Customers.Where(c => c.CustomerId == customerId).First();
customer.Name = txtName.Text;
customer.Surname = txtSurname.Text;
entityModel.SaveChanges();
gvCustomers.EditIndex = -1;
BindCustomers();
}