Hi
I have a user-control which uses the ViewState to persist some data between postbacks. But if I dynamically instantiate my control within a Repeater, it seems my control has no access to the ViewState - how do I get around this limitation?
See the below aspx, on which I place a web-user-control called WebUserControl5a.
It is placed (1) statically, (2) dynamically in a placeholder, and (3) dynamically in a placeholder in a Repeater.
WebUserControl5a uses the ViewState to contain a count, which it increments on every postback, and displays. This works fine, unless WebUserControl5a is dynamically instantiated in a Repeater. Why, and how do I work around this?
Note that I could achieve this "increment count" in other ways, but that is not the point of the exercise. I really want to persist data in the viewstate which I have access to.
Thanks!
WebForm5.aspx:
WebForm5.aspx.cs:
WebUserControl5a.ascx:
WebUserControl5a.ascx.cs:
WebUserControl5b.ascx:
WebUserControl5b.ascx.cs:
I have a user-control which uses the ViewState to persist some data between postbacks. But if I dynamically instantiate my control within a Repeater, it seems my control has no access to the ViewState - how do I get around this limitation?
See the below aspx, on which I place a web-user-control called WebUserControl5a.
It is placed (1) statically, (2) dynamically in a placeholder, and (3) dynamically in a placeholder in a Repeater.
WebUserControl5a uses the ViewState to contain a count, which it increments on every postback, and displays. This works fine, unless WebUserControl5a is dynamically instantiated in a Repeater. Why, and how do I work around this?
Note that I could achieve this "increment count" in other ways, but that is not the point of the exercise. I really want to persist data in the viewstate which I have access to.
Thanks!
WebForm5.aspx:
Code:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm5.aspx.cs" Inherits="WebApplication1.WebForm5" %>
<%@ Register TagPrefix="uc" TagName="WebUserControl5a" Src="WebUserControl5a.ascx" %>
<%@ Register TagPrefix="uc" TagName="WebUserControl5b" Src="WebUserControl5b.ascx" %>
<html xmlns="[URL unfurl="true"]http://www.w3.org/1999/xhtml">[/URL]
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
User control 5a directly on page:
<br />
<table border="1">
<tr>
<td>
<uc:WebUserControl5a ID="wuc5a" runat="server" />
</td>
</tr>
</table>
<br />
User control 5a dynamically instantiated in a placeholder on the page:
<br />
<table border="1">
<tr>
<td>
<asp:PlaceHolder ID="placeholderFor5a" runat="server" />
</td>
</tr>
</table>
<br />
User control 5a and 5b dynamically created in a repeater:
<br />
<table border="1">
<asp:Repeater ID="repeater1" runat="server" OnItemDataBound="Repeater1_ItemDataBound">
<ItemTemplate>
<tr>
<td>
Control = <asp:PlaceHolder ID="ph" runat="server" />
</td>
</tr>
</ItemTemplate>
</asp:Repeater>
</table>
<asp:Button ID="SaveBtn" runat="server" Text="save" onclick="SaveBtn_Click" />
</div>
</form>
</body>
</html>WebForm5.aspx.cs:
Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class WebForm5 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
WebUserControl5a wuc5a = LoadControl("WebUserControl5a.ascx") as WebUserControl5a;
placeholderFor5a.Controls.Add(wuc5a);
if (!IsPostBack)
{
IList<string> data = RetrieveData();
CurrentData = data;
}
else
{
IList<string> data = CurrentData;
CurrentData = data;
}
}
protected IList<string> CurrentData
{
get
{
return ViewState["DATA_LIST"] as IList<string>; ;
}
set
{
ViewState["DATA_LIST"] = value;
if (value != null)
{
repeater1.DataSource = value;
repeater1.DataBind();
}
else
{
}
}
}
private IList<string> RetrieveData()
{
IList<string> data = new List<string>();
data.Add("5a");
data.Add("5b");
return data;
}
protected void Repeater1_ItemDataBound(object sender, System.Web.UI.WebControls.RepeaterItemEventArgs e)
{
RepeaterItem item = e.Item;
if ((item.ItemType == ListItemType.Item) || (item.ItemType == ListItemType.AlternatingItem))
{
Control dynamicControl = null;
string controlType = item.DataItem as string;
if (controlType == "5a")
{
WebUserControl5a wc5a = LoadControl("WebUserControl5a.ascx") as WebUserControl5a;
dynamicControl = wc5a;
}
else if (controlType == "5b")
{
WebUserControl5b wc5b = LoadControl("WebUserControl5b.ascx") as WebUserControl5b;
dynamicControl = wc5b;
}
dynamicControl.ID = "dcontrol_" + item.ItemIndex;
PlaceHolder ph = (PlaceHolder)item.FindControl("ph");
ph.Controls.Add(dynamicControl);
}
}
protected void SaveBtn_Click(object sender, EventArgs e)
{
}
}
}WebUserControl5a.ascx:
Code:
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="WebUserControl5a.ascx.cs" Inherits="WebApplication1.WebUserControl5a" %>
This is WebUserControl5a<br />
<asp:TextBox ID="textbox5a" runat="server" /><br />
StateCount=<%= StateCount%>WebUserControl5a.ascx.cs:
Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class WebUserControl5a : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
int? count = StateCount;
if (count == null)
{
count = 0;
StateCount = count;
}
else
{
count++;
StateCount = count;
}
}
protected int? StateCount
{
get
{
return ViewState["COUNT_5A"] as int?;
}
set
{
ViewState["COUNT_5A"] = value;
}
}
protected string GetDataValue()
{
return textbox5a.Text;
}
}
}WebUserControl5b.ascx:
Code:
<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="WebUserControl5b.ascx.cs" Inherits="WebApplication1.WebUserControl5b" %>
This is WebUserControl5b<br />
<asp:TextBox ID="textbox5b" runat="server" />WebUserControl5b.ascx.cs:
Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class WebUserControl5b : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
}
}
}