模板化数据绑定控件示例
若要生成该示例，请参见服务器控件示例中的说明。 [C#] // TemplatedList.cs. namespace CustomControls { using System; using System.ComponentModel; using System.ComponentModel.Design; using System.ComponentModel.Design.Serialization; using System.Collections; using System.Diagnostics; using System.Web.UI; using System.Web.UI.WebControls; [ DefaultEvent("SelectedIndexChanged"), DefaultProperty("DataSource"), Designer("CustomControls.Design.TemplatedListDesigner, CustomControls.Design", typeof(IDesigner)) ] public class TemplatedList : WebControl, INamingContainer { #region Statics and Constants private static readonly object EventSelectedIndexChanged = new object(); private static readonly object EventItemCreated = new object(); private static readonly object EventItemDataBound = new object(); private static readonly object EventItemCommand = new object(); #endregion #region Member variables private IEnumerable dataSource; private TableItemStyle itemStyle; private TableItemStyle alternatingItemStyle; private TableItemStyle selectedItemStyle; private ITemplate itemTemplate; #endregion #region Properties [ Category("Style"), Description("The style to be applied to alternate items."), DesignerSerializationVisibility(DesignerSerializationVisibility.Content), NotifyParentProperty(true), PersistenceMode(PersistenceMode.InnerProperty), ] public virtual TableItemStyle AlternatingItemStyle { get { if (alternatingItemStyle == null) { alternatingItemStyle = new TableItemStyle(); if (IsTrackingViewState) ((IStateManager)alternatingItemStyle).TrackViewState(); } return alternatingItemStyle; } } [ Bindable(true), Category("Appearance"), DefaultValue(-1), Description("The cell padding of the rendered table.") ] public virtual int CellPadding { get { if (ControlStyleCreated == false) { return -1; } return ((TableStyle)ControlStyle).CellPadding; } set { ((TableStyle)ControlStyle).CellPadding = value; } } [ Bindable(true), Category("Appearance"), DefaultValue(0), Description("The cell spacing of the rendered table.") ] public virtual int CellSpacing { get { if (ControlStyleCreated == false) { return 0; } return ((TableStyle)ControlStyle).CellSpacing; } set { ((TableStyle)ControlStyle).CellSpacing = value; } } [ Bindable(true), Category("Data"), DefaultValue(null), Description("The data source used to build up the control."), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden) ] public IEnumerable DataSource { get { return dataSource; } set { dataSource = value; } } [ Bindable(true), Category("Appearance"), DefaultValue(GridLines.None), Description("The grid lines to be shown in the rendered table.") ] public virtual GridLines GridLines { get { if (ControlStyleCreated == false) { return GridLines.None; } return ((TableStyle)ControlStyle).GridLines; } set { ((TableStyle)ControlStyle).GridLines = value; } } [ Category("Style"), Description("The style to be applied to all items."), DesignerSerializationVisibility(DesignerSerializationVisibility.Content), NotifyParentProperty(true), PersistenceMode(PersistenceMode.InnerProperty), ] public virtual TableItemStyle ItemStyle { get { if (itemStyle == null) { itemStyle = new TableItemStyle(); if (IsTrackingViewState) ((IStateManager)itemStyle).TrackViewState(); } return itemStyle; } } [ Browsable(false), DefaultValue(null), Description("The content to be shown in each item."), PersistenceMode(PersistenceMode.InnerProperty), TemplateContainer(typeof(TemplatedListItem)) ] public virtual ITemplate ItemTemplate { get { return itemTemplate; } set { itemTemplate = value; } } [ Bindable(true), DefaultValue(-1), Description("The index of the selected item.") ] public virtual int SelectedIndex { get { object o = ViewState["SelectedIndex"]; if (o != null) return(int)o; return -1; } set { if (value < -1) { throw new ArgumentOutOfRangeException(); } int oldSelectedIndex = SelectedIndex; ViewState["SelectedIndex"] = value; if (HasControls()) { Table table = (Table)Controls[0]; TemplatedListItem item; if ((oldSelectedIndex != -1) && (table.Rows.Count > oldSelectedIndex)) { item = (TemplatedListItem)table.Rows[oldSelectedIndex]; if (item.ItemType != ListItemType.EditItem) { ListItemType itemType = ListItemType.Item; if (oldSelectedIndex % 2 != 0) itemType = ListItemType.AlternatingItem; item.SetItemType(itemType); } } if ((value != -1) && (table.Rows.Count > value)) { item = (TemplatedListItem)table.Rows[value]; item.SetItemType(ListItemType.SelectedItem); } } } } [ Category("Style"), Description("The style to be applied to the selected item."), DesignerSerializationVisibility(DesignerSerializationVisibility.Content), NotifyParentProperty(true), PersistenceMode(PersistenceMode.InnerProperty), ] public virtual TableItemStyle SelectedItemStyle { get { if (selectedItemStyle == null) { selectedItemStyle = new TableItemStyle(); if (IsTrackingViewState) ((IStateManager)selectedItemStyle).TrackViewState(); } return selectedItemStyle; } } #endregion #region Events protected virtual void OnItemCommand(TemplatedListCommandEventArgs e) { TemplatedListCommandEventHandler onItemCommandHandler = (TemplatedListCommandEventHandler)Events[EventItemCommand]; if (onItemCommandHandler != null) onItemCommandHandler(this, e); } protected virtual void OnItemCreated(TemplatedListItemEventArgs e) { TemplatedListItemEventHandler onItemCreatedHandler = (TemplatedListItemEventHandler)Events[EventItemCreated]; if (onItemCreatedHandler != null) onItemCreatedHandler(this, e); } protected virtual void OnItemDataBound(TemplatedListItemEventArgs e) { TemplatedListItemEventHandler onItemDataBoundHandler = (TemplatedListItemEventHandler)Events[EventItemDataBound]; if (onItemDataBoundHandler != null) onItemDataBoundHandler(this, e); } protected virtual void OnSelectedIndexChanged(EventArgs e) { EventHandler handler = (EventHandler)Events[EventSelectedIndexChanged]; if (handler != null) handler(this, e); } [ Category("Action"), Description("Raised when a CommandEvent occurs within an item.") ] public event TemplatedListCommandEventHandler ItemCommand { add { Events.AddHandler(EventItemCommand, value); } remove { Events.RemoveHandler(EventItemCommand, value); } } [ Category("Behavior"), Description("Raised when an item is created and is ready for customization.") ] public event TemplatedListItemEventHandler ItemCreated { add { Events.AddHandler(EventItemCreated, value); } remove { Events.RemoveHandler(EventItemCreated, value); } } [ Category("Behavior"), Description("Raised when an item is data-bound.") ] public event TemplatedListItemEventHandler ItemDataBound { add { Events.AddHandler(EventItemDataBound, value); } remove { Events.RemoveHandler(EventItemDataBound, value); } } [ Category("Action"), Description("Raised when the SelectedIndex property has changed.") ] public event EventHandler SelectedIndexChanged { add { Events.AddHandler(EventSelectedIndexChanged, value); } remove { Events.RemoveHandler(EventSelectedIndexChanged, value); } } #endregion #region Methods and Implementation protected override void CreateChildControls() { Controls.Clear(); if (ViewState["ItemCount"] != null) { // Create the control hierarchy using the view state, // not the data source. CreateControlHierarchy(false); } } private void CreateControlHierarchy(bool useDataSource) { IEnumerable dataSource = null; int count = -1; if (useDataSource == false) { // ViewState must have a non-null value for ItemCount because this is checked // by CreateChildControls. count = (int)ViewState["ItemCount"]; if (count != -1) { dataSource = new DummyDataSource(count); } } else { dataSource = this.dataSource; } if (dataSource != null) { Table table = new Table(); Controls.Add(table); int selectedItemIndex = SelectedIndex; int index = 0; count = 0; foreach (object dataItem in dataSource) { ListItemType itemType = ListItemType.Item; if (index == selectedItemIndex) { itemType = ListItemType.SelectedItem; } else if (index % 2 != 0) { itemType = ListItemType.AlternatingItem; } CreateItem(table, index, itemType, useDataSource, dataItem); count++; index++; } } if (useDataSource) { // Save the number of items contained for use in round trips. ViewState["ItemCount"] = ((dataSource != null) ? count : -1); } } protected override Style CreateControlStyle() { // Since the TemplatedList control renders an HTML table, // an instance of the TableStyle class is used as the control style. TableStyle style = new TableStyle(ViewState); // Set up default initial state. style.CellSpacing = 0; return style; } private TemplatedListItem CreateItem(Table table, int itemIndex, ListItemType itemType, bool dataBind, object dataItem) { TemplatedListItem item = new TemplatedListItem(itemIndex, itemType); TemplatedListItemEventArgs e = new TemplatedListItemEventArgs(item); if (itemTemplate != null) { itemTemplate.InstantiateIn(item.Cells[0]); } if (dataBind) { item.DataItem = dataItem; } OnItemCreated(e); table.Rows.Add(item); if (dataBind) { item.DataBind(); OnItemDataBound(e); item.DataItem = null; } return item; } public override void DataBind() { // Controls with a data-source property perform their custom data binding // by overriding DataBind. // Evaluate any data-binding expressions on the control itself. base.OnDataBinding(EventArgs.Empty); // Reset the control state. Controls.Clear(); ClearChildViewState(); // Create the control hierarchy using the data source. CreateControlHierarchy(true); ChildControlsCreated = true; TrackViewState(); } protected override void LoadViewState(object savedState) { // Customize state management to handle saving state of contained objects. if (savedState != null) { object[] myState = (object[])savedState; if (myState[0] != null) base.LoadViewState(myState[0]); if (myState[1] != null) ((IStateManager)ItemStyle).LoadViewState(myState[1]); if (myState[2] != null) ((IStateManager)SelectedItemStyle).LoadViewState(myState[2]); if (myState[3] != null) ((IStateManager)AlternatingItemStyle).LoadViewState(myState[3]); } } protected override bool OnBubbleEvent(object source, EventArgs e) { // Handle events raised by children by overriding OnBubbleEvent. bool handled = false; if (e is TemplatedListCommandEventArgs) { TemplatedListCommandEventArgs ce = (TemplatedListCommandEventArgs)e; OnItemCommand(ce); handled = true; if (String.Compare(ce.CommandName, "Select", true) == 0) { SelectedIndex = ce.Item.ItemIndex; OnSelectedIndexChanged(EventArgs.Empty); } } return handled; } private void PrepareControlHierarchy() { if (HasControls() == false) { return; } Debug.Assert(Controls[0] is Table); Table table = (Table)Controls[0]; table.CopyBaseAttributes(this); if (ControlStyleCreated) { table.ApplyStyle(ControlStyle); } // The composite alternating item style; do just one // merge style on the actual item. Style altItemStyle = null; if (alternatingItemStyle != null) { altItemStyle = new TableItemStyle(); altItemStyle.CopyFrom(itemStyle); altItemStyle.CopyFrom(alternatingItemStyle); } else { altItemStyle = itemStyle; } int rowCount = table.Rows.Count; for (int i = 0; i < rowCount; i++) { TemplatedListItem item = (TemplatedListItem)table.Rows[i]; Style compositeStyle = null; switch (item.ItemType) { case ListItemType.Item: compositeStyle = itemStyle; break; case ListItemType.AlternatingItem: compositeStyle = altItemStyle; break; case ListItemType.SelectedItem: { compositeStyle = new TableItemStyle(); if (item.ItemIndex % 2 != 0) compositeStyle.CopyFrom(altItemStyle); else compositeStyle.CopyFrom(itemStyle); compositeStyle.CopyFrom(selectedItemStyle); } break; } if (compositeStyle != null) { item.MergeStyle(compositeStyle); } } } protected override void Render(HtmlTextWriter writer) { // Apply styles to the control hierarchy // and then render it out. // Apply styles during render phase, so the user can change styles // after calling DataBind without the property changes ending // up in view state. PrepareControlHierarchy(); RenderContents(writer); } protected override object SaveViewState() { // Customized state management to handle saving state of contained objects such as styles. object baseState = base.SaveViewState(); object itemStyleState = (itemStyle != null) ? ((IStateManager)itemStyle).SaveViewState() : null; object selectedItemStyleState = (selectedItemStyle != null) ? ((IStateManager)selectedItemStyle).SaveViewState() : null; object alternatingItemStyleState = (alternatingItemStyle != null) ? ((IStateManager)alternatingItemStyle).SaveViewState() : null; object[] myState = new object[4]; myState[0] = baseState; myState[1] = itemStyleState; myState[2] = selectedItemStyleState; myState[3] = alternatingItemStyleState; return myState; } protected override void TrackViewState() { // Customized state management to handle saving state of contained objects such as styles. base.TrackViewState(); if (itemStyle != null) ((IStateManager)itemStyle).TrackViewState(); if (selectedItemStyle != null) ((IStateManager)selectedItemStyle).TrackViewState(); if (alternatingItemStyle != null) ((IStateManager)alternatingItemStyle).TrackViewState(); } #endregion } public class TemplatedListItem : TableRow, INamingContainer { private int itemIndex; private ListItemType itemType; private object dataItem; public TemplatedListItem(int itemIndex, ListItemType itemType) { this.itemIndex = itemIndex; this.itemType = itemType; Cells.Add(new TableCell()); } public virtual object DataItem { get { return dataItem; } set { dataItem = value; } } public virtual int ItemIndex { get { return itemIndex; } } public virtual ListItemType ItemType { get { return itemType; } } protected override bool OnBubbleEvent(object source, EventArgs e) { if (e is CommandEventArgs) { // Add the information about Item to CommandEvent. TemplatedListCommandEventArgs args = new TemplatedListCommandEventArgs(this, source, (CommandEventArgs)e); RaiseBubbleEvent(this, args); return true; } return false; } internal void SetItemType(ListItemType itemType) { this.itemType = itemType; } } public sealed class TemplatedListCommandEventArgs : CommandEventArgs { private TemplatedListItem item; private object commandSource; public TemplatedListCommandEventArgs(TemplatedListItem item, object commandSource, CommandEventArgs originalArgs) : base(originalArgs) { this.item = item; this.commandSource = commandSource; } public TemplatedListItem Item { get { return item; } } public object CommandSource { get { return commandSource; } } } public delegate void TemplatedListCommandEventHandler(object source, TemplatedListCommandEventArgs e); public sealed class TemplatedListItemEventArgs : EventArgs { private TemplatedListItem item; public TemplatedListItemEventArgs(TemplatedListItem item) { this.item = item; } public TemplatedListItem Item { get { return item; } } } public delegate void TemplatedListItemEventHandler(object sender, TemplatedListItemEventArgs e); internal sealed class DummyDataSource : ICollection { private int dataItemCount; public DummyDataSource(int dataItemCount) { this.dataItemCount = dataItemCount; } public int Count { get { return dataItemCount; } } public bool IsReadOnly { get { return false; } } public bool IsSynchronized { get { return false; } } public object SyncRoot { get { return this; } } public void CopyTo(Array array, int index) { for (IEnumerator e = this.GetEnumerator(); e.MoveNext();) array.SetValue(e.Current, index++); } public IEnumerator GetEnumerator() { return new DummyDataSourceEnumerator(dataItemCount); } private class DummyDataSourceEnumerator : IEnumerator { private int count; private int index; public DummyDataSourceEnumerator(int count) { this.count = count; this.index = -1; } public object Current { get { return null; } } public bool MoveNext() { index++; return index < count; } public void Reset() { this.index = -1; } } } } 以下示例说明使用 [C#]
<%@ Page language="C#" %>
<%@ Register TagPrefix="custom" Namespace="CustomControls" Assembly="CustomControls"%>
<html>
<head>
<title>Data-Bound Control Sample</title>
</head>
<body>
<form runat="server">
<h3>TemplatedList Control Sample</h3>
<hr>
<custom:TemplatedList runat="server" id="myList"
Font-Name="Verdana" Font-Size="16pt"
BorderColor="Gray" BorderWidth="1px"
CellSpacing="0" CellPadding="2" GridLines="Both"
onItemCreated="MyList_ItemCreated"
onSelectedIndexChanged="MyList_SelectedIndexChanged">
<ItemStyle ForeColor="Black" BackColor="#EEEEEE"/>
<AlternatingItemStyle BackColor="#DCDCDC"/>
<SelectedItemStyle ForeColor="White" BackColor="#000084"/>
<ItemTemplate>
<asp:Button runat="server" id="selectButton" CommandName="Select"
Text="Select" ForeColor="Blue"></asp:Button>
<asp:Label runat="server" Text='<%# Container.DataItem %>'/>
</ItemTemplate>
</custom:TemplatedList>
<hr>
<asp:Label runat="server" id="infoLabel"></asp:Label>
<hr>
</form>
<script runat="server">
private int selectedIndex = -1;
private void LoadData() {
ArrayList data = new ArrayList();
for (int i = 0; i < 10; i++) {
data.Add("Item " + i);
}
myList.DataSource = data;
myList.DataBind();
}
protected override void OnLoad(EventArgs e) {
base.OnLoad(e);
if (!IsPostBack) {
LoadData();
}
}
protected void MyList_ItemCreated(object sender, TemplatedListItemEventArgs e) {
if (e.Item.ItemType == ListItemType.SelectedItem) {
selectedIndex = e.Item.ItemIndex;
Button selectButton = (Button)e.Item.FindControl("selectButton");
selectButton.Enabled = false;
}
}
protected void MyList_SelectedIndexChanged(object sender, EventArgs e) {
if (selectedIndex != -1) {
Control item = myList.Controls[0].Controls[selectedIndex];
Button selectButton = (Button)item.FindControl("selectButton");
selectButton.Enabled = true;
}
selectedIndex = myList.SelectedIndex;
infoLabel.Text = "SelectedIndex: " + selectedIndex;
if (selectedIndex != -1) {
Control item = myList.Controls[0].Controls[selectedIndex];
Button selectButton = (Button)item.FindControl("selectButton");
selectButton.Enabled = false;
}
}
</script>
</body>
</html>
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