Binding issues with GridView in ASP.NET - asp.net

Question

I am totally confused with the way ASP.NET GridView binding works.
I have a GridView. Now, on the page load (using !IsPostBack) I am binding the GridView.
My gridview has an edit button. When I click on it, the GridView becomes blank. Behaviour could be expected, because when I click on the edit button, a postback happens and, because I have binded the GridView inside the !IsPostback condition, it won't bind the GridView.
Now, if I remove the GridView binding, and place it outside the !IsPostback condition, the edit button works. But, I am unable to get the edited value from the TextBox. In this case, too, the behaviour could be expected, as when the update button is clicked, the GridView is re-binded, because the binding this time has been done outside the !IsPostback condition.
So, I want to know what could be the proper code for the edit button to work, and at the same time, the edited values from the TextBox could be retrieved.
Question Updated with Code:
<asp:GridView ID="grdExternalLinkSection1" ShowFooter="true" runat="server" Width="100%" AutoGenerateColumns="false" CellPadding="5" EnableViewState="true">
<EmptyDataTemplate>
External Link Title
<asp:TextBox ID="txtExternalLinkTitleEmptySection1" runat="server"></asp:TextBox>
External Link Url
<asp:TextBox ID="txtExternalLinkUrlEmptySection1" runat="server"></asp:TextBox>
<asp:Button ID="btnExternalLinkEmptySection1" OnCommand="grdExternalLinkSection_Button_Clicks" runat="server" Text="Add" CommandName="headernew,1" style="padding:3px; width:56px;" />
</EmptyDataTemplate>
<Columns>
<asp:TemplateField HeaderText="Title">
<ItemTemplate>
<asp:Label ID="lblExternalLinkTitleSection1" runat="server"><%# Eval("Title") %></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txtExternalLinkTitleEditSection1" runat="server" Text='<%# Bind("Title") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="txtExternalLinkTitleFooterSection1" runat="server"></asp:TextBox>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Url">
<ItemTemplate>
<asp:Label ID="lblExternalLinkUrlSection1" runat="server"><%# Eval("Url")%></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txtExternalLinkUrlEditSection1" runat="server" Text='<%# Bind("Url") %>'></asp:TextBox>
</EditItemTemplate>
<FooterTemplate>
<asp:TextBox ID="txtExternalLinkUrlFooterSection1" runat="server"></asp:TextBox>
</FooterTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Manage">
<ItemTemplate>
<asp:Button ID="btnExternalLinkEditSection1" OnCommand="grdExternalLinkSection_Button_Clicks" runat="server" CommandName="Editing,1" CommandArgument='<%# Container.DataItemIndex %>' Text="Edit" />
<asp:Button ID="btnExternalLinkDeleteSection1" OnCommand="grdExternalLinkSection_Button_Clicks" runat="server" CommandName="Deleting,1" CommandArgument='<%# Container.DataItemIndex %>' Text="Delete" />
</ItemTemplate>
<EditItemTemplate>
<asp:Button ID="btnExternalLinkUpdateSection1" OnCommand="grdExternalLinkSection_Button_Clicks" runat="server" CommandName="Updating,1" CommandArgument='<%# Container.DataItemIndex %>' Text="Update" />
<asp:Button ID="btnExternalLinkCancelSection1" OnCommand="grdExternalLinkSection_Button_Clicks" runat="server" CommandName="Canceling,1" CommandArgument='<%# Container.DataItemIndex %>' Text="Cancel" />
</EditItemTemplate>
<FooterTemplate>
<asp:Button ID="btnExternalLinkAddFooterSection1" OnCommand="grdExternalLinkSection_Button_Clicks" runat="server" CommandName="Footer,1" Text="Add" />
</FooterTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
below is the function which does the binding work:
GridView grid;
protected void BindExternalLinks(int SectionID, string ControlName)
{
using (SqlConnection connection = new SqlConnection(connectionString))
{
using (SqlDataAdapter adapter = new SqlDataAdapter("user_Newsletter_GetExternalLinks", connection))
{
adapter.SelectCommand.CommandType = CommandType.StoredProcedure;
adapter.SelectCommand.Parameters.Add("#SectionID", SqlDbType.Int).Value = SectionID;
adapter.SelectCommand.Parameters.Add("#PortalID", SqlDbType.Int).Value = PortalID;
DataTable dt = new DataTable();
adapter.Fill(dt);
grid = (GridView)this.FindControl(ControlName);
grid.DataSource = dt;
}
}
}
protected void BindAllExternalLinks()
{
for (int i = 1; i <= NewsLetterSectionCount; i++)
{
BindExternalLinks(i, "grdExternalLinkSection" + i);
grid.DataBind();
}
}
below is my PageLoad:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindAllExternalLinks();
}
}
and below is my command buttons event: i have kept the handler common for all command buttons:
protected void grdExternalLinkSection_Button_Clicks(object sender, CommandEventArgs e)
{
int rowIndex = (e.CommandArgument != "") ? Convert.ToInt32(e.CommandArgument) : -1;
string[] commandNames = e.CommandName.ToString().Split(',');
string command = commandNames[0].ToString().ToLower();
int sectionID = Convert.ToInt32(commandNames[1]);
GridView grid = (GridView)this.FindControl("grdExternalLinkSection" + sectionID);
try
{
if (command == "headernew")
{
TextBox title = grid.Controls[0].Controls[0].FindControl("txtExternalLinkTitleEmptySection" + sectionID) as TextBox;
TextBox url = grid.Controls[0].Controls[0].FindControl("txtExternalLinkUrlEmptySection" + sectionID) as TextBox;
UpdateExternalLinks(ModifyExternalLinks.Insert, sectionID, title.Text, url.Text);
MessageShow("External Link Added Successfully");
}
else if (command == "editing")
{
//grid.EditIndex = rowIndex;
}
else if (command == "canceling")
{
grid.EditIndex = -1;
}
else if (command == "footer")
{
Response.Write("Inside Footer");
}
}
catch (Exception ex)
{
Response.Write(ex.ToString());
}
BindExternalLinks(sectionID, "grdExternalLinkSection" + sectionID);
grid.DataBind(); //here i am binding once the records are modified.
}

Answer 1

You are almost there. BindAllExternalLinks() should be inside the if (!IsPostback) block, correct.
The additional thing you should do is to rebind the grid after you have done your editing:
else if (command == "editing")
{
// do your update stuff here
BindAllExternalLinks();
}

Answer 2

Just rebind the gridview under each postback event(). Even if you bind it to an object datasource or SQL DataSource, you have to call the databind method after every postback request like
MyGridview.DataBind();
UpdatePanel1.Update();