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POASP.NET - Problem with GridView with Dynamic Columns
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  1. POASP.NET - Problem with GridView with Dynamic Columns
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    copied!<p>I have a GridView that includes BoundField and TemplateField elements. Some of the TemplateField elements are dynamically generated. For the sake of reference, here is the GridView that I am using</p> <pre><code> &lt;asp:GridView ID="myGridView" runat="server" AutoGenerateColumns="False" DataKeyNames="ID" ShowFooter="True" EnableModelValidation="True" OnLoad="myGridView_Load" OnRowCommand="myGridView_RowCommand" OnRowEditing="myGridView_RowEditing" OnRowDeleting="myGridView_RowDeleting" OnRowCancelingEdit="myGridView_RowCancelingEdit" OnRowUpdating="myGridView_RowUpdating"&gt; &lt;Columns&gt; &lt;asp:BoundField DataField="Number" Visible="true" HeaderText="Test" /&gt; &lt;asp:TemplateField HeaderText="Number"&gt; &lt;EditItemTemplate&gt; &lt;asp:TextBox ID="tb1" runat="server" Text='&lt;%# Bind("Number") %&gt;' /&gt; &lt;/EditItemTemplate&gt; &lt;ItemTemplate&gt; &lt;asp:Label ID="lb1" runat="server" Text='&lt;%# Bind("Number") %&gt;' /&gt; &lt;/ItemTemplate&gt; &lt;FooterTemplate&gt; &lt;asp:TextBox ID="ftb" runat="server" Text="[x]" /&gt; &lt;/FooterTemplate&gt; &lt;/asp:TemplateField&gt; &lt;%-- Dynamically Generated Columns Will Be Inserted Here --%&gt; &lt;asp:TemplateField HeaderText="Actions"&gt; &lt;EditItemTemplate&gt; &lt;asp:LinkButton ID="ulb" runat="server" Text="update" CommandName="Update" /&gt; &lt;asp:LinkButton ID="clb" runat="server" Text="cancel" CommandName="Cancel" /&gt; &lt;/EditItemTemplate&gt; &lt;FooterTemplate&gt; &lt;asp:LinkButton ID="slb" runat="server" Text="insert" OnClick="saveLinkButton_Click" /&gt; &lt;/FooterTemplate&gt; &lt;ItemTemplate&gt; &lt;asp:LinkButton ID="elb" runat="server" Text="edit" CommandName="Edit" /&gt; &lt;asp:LinkButton ID="dlb" runat="server" Text="delete" CommandName="Delete" /&gt; &lt;/ItemTemplate&gt; &lt;/asp:TemplateField &lt;/Columns&gt; &lt;EmptyDataTemplate&gt; &lt;table border="0" cellpadding="0" cellspacing="0"&gt; &lt;tr&gt;&lt;td&gt;Number&lt;/td&gt;&lt;/tr&gt; &lt;tr&gt; &lt;td&gt;&lt;asp:TextBox ID="ntb" runat="server" /&gt;&lt;/td&gt; &lt;td&gt;&lt;asp:LinkButton ID="slb2" runat="server" Text="save" OnClick="saveLinkButton_Click" /&gt;&lt;/td&gt; &lt;/tr&gt; &lt;/table&gt; &lt;/EmptyDataTemplate&gt; &lt;/asp:GridView&gt; </code></pre> <p>When the GridView initially loads, everything is loaded properly. However, anytime I perform a command (edit, insert, delete), all of the data goes away. Oddly, the BoundField values still appear correctly. However, any TemplateField does not seem to get rendered. The code that I am using to work with this GridView is here:</p> <pre><code>public partial class GridView : System.Web.UI.Page { private List&lt;string&gt; dynamicColumnNames = new List&lt;string&gt;(); protected void Page_Load(object sender, EventArgs e) { LoadPageData(); } protected void saveLinkButton_Click(object sender, EventArgs e) { } protected void myGridView_Load(object sender, EventArgs e) { if (Page.IsPostBack == false) { BindGridData(); } } protected void myGridView_RowCommand(object sender, GridViewCommandEventArgs e) { } protected void myGridView_RowEditing(object sender, GridViewEditEventArgs e) { myGridView.EditIndex = e.NewEditIndex; BindGridData(); } protected void myGridView_RowDeleting(object sender, GridViewDeleteEventArgs e) { LoadPageData(); BindGridData(); } protected void myGridView_RowCancelingEdit(object sender, EventArgs e) { myGridView.EditIndex = -1; BindGridData(); } protected void myGridView_RowUpdating(object sender, GridViewUpdateEventArgs e) { myGridView.EditIndex = -1; LoadPageData(); BindGridData(); } private void BindGridData() { // Create a temporary data source DataTable tempData = new DataTable(); tempData.Columns.Add("ID"); tempData.Columns.Add("Number"); // Dynamically add template columns foreach (string columnName in dynamicColumnNames) { tempData.Columns.Add(columnName); TemplateField templateField = new TemplateField(); templateField.HeaderTemplate = new MyTemplateField(ListItemType.Header, columnName); templateField.ItemTemplate = new MyTemplateField(ListItemType.Item, columnName); templateField.EditItemTemplate = new MyTemplateField(ListItemType.EditItem, columnName); templateField.FooterTemplate = new MyTemplateField(ListItemType.Footer, columnName); myGridView.Columns.Insert(2, templateField); } // Add some phony data Random random = new Random(DateTime.Now.Millisecond); for (int i = 0; i &lt; 10; i++) { DataRow tempRow = tempData.NewRow(); tempRow["Number"] = (i + 1); foreach (string column in dynamicColumnNames) tempRow[column] = random.NextDouble(); tempData.Rows.Add(tempRow); } // Bind the data to the grid myGridView.DataSource = tempData; myGridView.DataBind(); } private void LoadPageData() { dynamicColumnNames.Add("USA"); dynamicColumnNames.Add("Japan"); dynamicColumnNames.Add("Mexico"); } } internal class MyTemplateField : ITemplate { // The type of the list item private ListItemType listItemType; // The value to use during instantiation private string value1 = string.Empty; public MyTemplateField(ListItemType listItemType, string value1) { this.listItemType = listItemType; this.value1 = value1; } public void InstantiateIn(Control container) { if (listItemType == ListItemType.Item) { TextBox textBox = new TextBox(); textBox.ReadOnly = true; textBox.DataBinding += new EventHandler(textBox_DataBinding); container.Controls.Add(textBox); } else if (listItemType == ListItemType.EditItem) { TextBox textBox = new TextBox(); textBox.DataBinding += new EventHandler(textBox_DataBinding); container.Controls.Add(textBox); } else if (listItemType == ListItemType.Header) { Literal literal = new Literal(); literal.Text = value1; container.Controls.Add(literal); } else if (listItemType == ListItemType.Footer) { TextBox textBox = new TextBox(); container.Controls.Add(textBox); } } private void textBox_DataBinding(object sender, EventArgs e) { TextBox textBox = (TextBox)(sender); GridViewRow row = (GridViewRow)(textBox.NamingContainer); textBox.Text = DataBinder.Eval(row.DataItem, value1).ToString(); } } </code></pre> <p>How do I use commands in a GridView with Dynamically added columns? What is wrong with my code?</p> <p>Thank you!</p>
 

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