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POCreating dynamic controls in Page_PreRender based on viewstate causes button OnClick event to not work
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  1. POCreating dynamic controls in Page_PreRender based on viewstate causes button OnClick event to not work
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    copied!<p>I realize that dynamic controls should be created within Page_Load and Page_Init in order for them to be registered in the control tree.</p> <p>I have created a custom control that requires the use of ViewState in a button OnClick event. This ViewState is then used to dynamically create controls.</p> <p>Since the life-cycle will go: Page Load -> Button Click -> Page PreRender. The view-state will not be updated until "Button Click", thus I am creating my dynamic controls in Page PreRender. However, creating a button and programatically assigning the OnClick EventHandler in Page_PreRender does not work.</p> <p>Does anyone know how I can get this to work? </p> <p>btn_DeleteTableRow_Click will not fire. This is setup in CreatePartRows()</p> <p>Here is my example:</p> <pre><code>&lt;asp:UpdatePanel ID="up_RMAPart" runat="server" UpdateMode="Conditional" EnableViewState="true" ChildrenAsTriggers="true"&gt; &lt;ContentTemplate&gt; &lt;div class="button" style="width: 54px; margin: 0px; float: right;"&gt; &lt;asp:Button ID="btn_AddPart" runat="server" Text="Add" OnClick="btn_AddPart_Click" /&gt; &lt;/div&gt; &lt;asp:Table ID="Table_Parts" runat="server" CssClass="hor-zebra"&gt; &lt;/asp:Table&gt; &lt;div class="clear"&gt;&lt;/div&gt; &lt;/ContentTemplate&gt; &lt;Triggers&gt; &lt;asp:AsyncPostBackTrigger ControlID="btn_AddPart" EventName="Click" /&gt; &lt;/Triggers&gt; </code></pre> <p></p> <p>Code Behind:</p> <pre><code>[Serializable] public struct Part { public string PartName; public int Quantity; public int PartID; public Part(string sPartName, int iQuantity, int iPartID) { PartName = sPartName; Quantity = iQuantity; PartID = iPartID; } } public partial class RMAPart : System.Web.UI.UserControl { private Dictionary&lt;string,Part&gt; m_RMAParts; private int m_RowNumber = 0; public Dictionary&lt;string, Part&gt; RMAParts { get { if (ViewState["m_RMAParts"] != null) return (Dictionary&lt;string, Part&gt;)ViewState["m_RMAParts"]; else return null; } set { ViewState["m_RMAParts"] = value; } } public int RowNumber { get { if (ViewState["m_RowNumber"] != null) return Convert.ToInt32(ViewState["m_RowNumber"]); else return 0; } set { ViewState["m_RowNumber"] = value; } } protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { RMAParts = new Dictionary&lt;string, Part&gt;(); RowNumber = 0; RMAParts.Add("PartRow_" + RowNumber.ToString(), new Part()); RowNumber = 1; CreatePartRows(); } } protected void Page_PreRender(object sender, EventArgs e) { CreatePartRows(); } private void CreatePartRows() { Table_Parts.Controls.Clear(); TableHeaderRow thr = new TableHeaderRow(); TableHeaderCell thc1 = new TableHeaderCell(); thc1.Controls.Add(new LiteralControl("Part")); thr.Cells.Add(thc1); TableHeaderCell thc2 = new TableHeaderCell(); thc2.Controls.Add(new LiteralControl("Quantity")); thr.Cells.Add(thc2); TableHeaderCell thc3 = new TableHeaderCell(); thc3.Controls.Add(new LiteralControl("")); thr.Cells.Add(thc3); Table_Parts.Rows.Add(thr); foreach (KeyValuePair&lt;string, Part&gt; kvp in RMAParts) { string[] sKey = kvp.Key.Split('_'); TableRow tr = new TableRow(); tr.ID = kvp.Key; TableCell tc1 = new TableCell(); TextBox tb_Part = new TextBox(); tb_Part.ID = "tb_Part_" + sKey[1]; tb_Part.CssClass = "textbox1"; tc1.Controls.Add(tb_Part); tr.Cells.Add(tc1); TableCell tc2 = new TableCell(); TextBox tb_Quantity = new TextBox(); tb_Quantity.ID = "tb_Quanitty_" + sKey[1]; tb_Quantity.CssClass = "textbox1"; tc2.Controls.Add(tb_Quantity); tr.Cells.Add(tc2); TableCell tc3 = new TableCell(); Button btn_Delete = new Button(); btn_Delete.ID = "btn_Delete_" + sKey[1]; btn_Delete.CommandArgument = tr.ID; btn_Delete.Click += new EventHandler(btn_DeleteTableRow_Click); btn_Delete.Text = "Remove"; tc3.Controls.Add(btn_Delete); tr.Cells.Add(tc3); Table_Parts.Rows.Add(tr); } } public void Reset() { Table_Parts.Controls.Clear(); RMAParts.Clear(); RowNumber = 0; RMAParts.Add("PartRow_" + RowNumber.ToString(), new Part()); RowNumber = 1; CreatePartRows(); } protected void btn_AddPart_Click(object sender, EventArgs e) { RMAParts.Add("PartRow_" + RowNumber.ToString(), new Part()); RowNumber++; } protected void btn_DeleteTableRow_Click(object sender, EventArgs e) { Button btn = (Button)sender; TableRow tr = (TableRow)Table_Parts.FindControl(btn.CommandArgument); Table_Parts.Rows.Remove(tr); RMAParts.Remove(btn.CommandArgument); } } </code></pre>
 

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