I need to make a Multi-select DataGrid in asp.net, for which I created a class (MultiGrid) in the code behind (C #).
namespace Portal { public class MultiGrid : DataGrid { // Constructor that sets some styles and graphical properties public MultiGrid() { AllowMultiSelect = false; AllowMultiSelectFooter = false; // Set event handlers Init += new EventHandler(OnInit); ItemCreated += new DataGridItemEventHandler(OnItemCreated); } // PROPERTY: SelectedItems public ArrayList SelectedItems { get { if (!AllowMultiSelect) return null; ArrayList a = new ArrayList(); foreach (DataGridItem dgi in Items) { CheckBox cb = (CheckBox)dgi.Cells[0].Controls[0]; if (cb.Checked) a.Add(dgi); } return a; } } // PROPERTY: AllowMultiSelect public bool AllowMultiSelect = false; // PROPERTY: AllowMultiSelectFooter public bool AllowMultiSelectFooter = false; // METHOD: ClearSelection public void ClearSelection() { foreach (DataGridItem dgi in Items) { CheckBox cb = (CheckBox)dgi.Cells[0].Controls[0]; cb.Checked = false; } } /////////////////////////////////////////////////////////////////// // Event Handlers // EVENT HANDLER: Init private void OnInit(Object sender, EventArgs e) { // Add a templated column that would allow for selection. // The item template contains a checkbox. It also features a // templated footer containing links for Unselect/Select all if (AllowMultiSelect) AddSelectColumn(); } // EVENT HANDLER: Deselect private void OnDeselect(Object sender, EventArgs e) { ClearSelection(); } // EVENT HANDLER: ItemCreated private void OnItemCreated(Object sender, DataGridItemEventArgs e) { // Get the newly created item ListItemType itemType = e.Item.ItemType; /////////////////////////////////////////////////////////////// // FOOTER if (itemType == ListItemType.Footer && AllowMultiSelectFooter && AllowMultiSelect) { // Look for a link button called "lnkSelect" in the context // of the grid item that represents the footer LinkButton lb = (LinkButton) e.Item.FindControl("lnkDeselect"); // Now you hold the living instance of the link // button in the footer and can bind it to any code in the // context of the MultiGrid control lb.Click += new EventHandler(OnDeselect); // Force ShowFooter to true ShowFooter = true; // Removes all the cells but the first TableCell cell = e.Item.Cells[0]; for (int i = 1; i < Columns.Count; i++) { e.Item.Cells.RemoveAt(1); } cell.ColumnSpan = Columns.Count; } } /////////////////////////////////////////////////////////////////// // Helper Functions private void AddSelectColumn() { // Create the new templated column TemplateColumn tc = new TemplateColumn(); tc.ItemStyle.BackColor = Color.SkyBlue; tc.ItemTemplate = new SelectColumnTemplate(); tc.FooterTemplate = new SelectFooterTemplate(); Columns.AddAt(0, tc); } } /////////////////////////////////////////////////////////////////////// // Template Classes public class SelectColumnTemplate : ITemplate { public void InstantiateIn(Control container) { CheckBox cb = new CheckBox(); container.Controls.Add(cb); } } public class SelectFooterTemplate : ITemplate { public void InstantiateIn(Control container) { LinkButton lb = new LinkButton(); lb.Text = "Deselect all"; lb.ID = "lnkDeselect"; container.Controls.Add(lb); } } }
Problem . I need to access this class in an aspx file, but it shows "The MultiGrid element is not a known element." My aspx code.
<%@ Register TagPrefix="expo" Namespace="Portal" Assembly="MultiGrid" %> <expo:MultiGrid id="grid" runat="server" AutoGenerateColumns="false" AllowMultiSelect="true" AllowMultiSelectFooter="true" font-size="x-small" font-names="verdana" BorderStyle="solid" BorderWidth="1" GridLines="both">
Any help would be appreciated.
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