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ListView.md

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ListView

The ListView component is meant to emulate the asp:ListView control in markup and is defined in the System.Web.UI.WebControls.ListView class

Usage Notes | Web Forms Syntax | Blazor Syntax

Features supported in Blazor

  • Alternating Item Templates
  • Alternating Item Styles
  • Empty Data Template
  • Empty Item Template
  • Grouping
  • Item Templates
  • Item Styles
  • Model Binding
    • OnSelect Method
  • LayoutTemplate
  • DataBinder within the ItemTemplate and AlternatingItemTemplate
  • ListViewItem and ListViewDataItem for event handling
  • CRUD Operations (Edit, Delete, Insert, Update, Cancel)
    • EditItemTemplate
    • InsertItemTemplate
    • EditIndex
    • InsertItemPosition
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ListViewItem and ListViewDataItem

The OnItemDataBound event provides a ListViewItemEventArgs object that contains a ListViewItem instance. For data items, this will be a ListViewDataItem object with the following properties:

  • ItemType - The type of item (DataItem, InsertItem, or EmptyItem)
  • DisplayIndex - The position of the item as displayed in the ListView
  • DataItemIndex - The index of the data item in the underlying data source
  • DataItem - The underlying data object bound to this item

Example:

void ItemDataBound(ListViewItemEventArgs e)
{
    if (e.Item.ItemType == ListViewItemType.DataItem)
    {
        var dataItem = (ListViewDataItem)e.Item;
        var widget = (Widget)dataItem.DataItem;
        // Access widget.Name, widget.Price, etc.
    }
}
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Usage Notes

  • LayoutTemplate - Requires a Context attribute that defines the placeholder for the items
  • Context attribute - For Web Forms compatibility, use Context="Item" on the ListView to access the current item as @Item in ItemTemplate and AlternatingItemTemplate instead of Blazor's default @context
  • ItemType attribute - Required to specify the type of items in the collection
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Web Forms Declarative Syntax

<asp:ListView  
    ConvertEmptyStringToNull="True|False"  
    DataKeyNames="string"  
    DataMember="string"  
    DataSource="string"  
    DataSourceID="string"  
    EditIndex="integer"  
    Enabled="True|False"  
    EnableTheming="True|False"  
    EnableViewState="True|False"  
    GroupPlaceholderID="string"  
    GroupItemCount="integer"  
    ID="string"  
    InsertItemPosition="None|FirstItem|LastItem"  
    ItemPlaceholderID="string"  
    OnDataBinding="DataBinding event handler"  
    OnDataBound="DataBound event handler"  
    OnDisposed="Disposed event handler"  
    OnInit="Init event handler"  
    OnItemCanceling="ItemCanceling event handler"  
    OnItemCommand="ItemCommand event handler"  
    OnItemCreated="ItemCreated event handler"  
    OnItemDataBound="ItemDataBound event handler"  
    OnItemDeleted="ItemDeleted event handler"  
    OnItemDeleting="ItemDeleting event handler"  
    OnItemEditing="ItemEditing event handler"  
    OnItemInserted="ItemInserted event handler"  
    OnItemInserting="ItemInserting event handler"  
    OnItemUpdated="ItemUpdated event handler"  
    OnItemUpdating="ItemUpdating event handler"  
    OnLayoutCreated="LayoutCreated event handler"  
    OnLoad="Load event handler"  
    OnPagePropertiesChanged="PagePropertiesChanged event handler"  
    OnPagePropertiesChanging="PagePropertiesChanging event handler"  
    OnPreRender="PreRender event handler"  
    OnSelectedIndexChanged="SelectedIndexChanged event handler"  
    OnSelectedIndexChanging="SelectedIndexChanging event handler"  
    OnSorted="Sorted event handler"  
    OnSorting="Sorting event handler"  
    OnUnload="Unload event handler"  
    runat="server"  
    SelectedIndex="integer"  
    SkinID="string"  
    Style="string"  
    Visible="True|False">  
    <AlternatingItemTemplate>  
        <!-- child controls -->  
    </AlternatingItemTemplate>  
    <EditItemTemplate>  
        <!-- child controls -->  
    </EditItemTemplate>  
    <EmptyDataTemplate>  
        <!-- child controls -->  
    </EmptyDataTemplate>  
    <EmptyItemTemplate>  
        <!-- child controls -->  
    </EmptyItemTemplate>  
    <GroupSeparatorTemplate>  
        <!-- child controls -->  
    </GroupSeparatorTemplate>  
    <GroupTemplate>  
        <!-- child controls -->  
    </GroupTemplate>  
    <InsertItemTemplate>  
        <!-- child controls -->  
    </InsertItemTemplate>  
    <ItemSeparatorTemplate>  
        <!-- child controls -->  
    </ItemSeparatorTemplate>  
    <ItemTemplate>  
        <!-- child controls -->  
    </ItemTemplate>  
    <LayoutTemplate>  
            <!-- child controls -->  
    </LayoutTemplate>  
    <SelectedItemTemplate>  
        <!-- child controls -->  
    </SelectedItemTemplate>  
</asp:ListView>
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Blazor Syntax

<ListView Context="Item"
          ItemType="Widget"
          EditIndex="@editIndex"
          InsertItemPosition="InsertItemPosition.LastItem"
          ItemEditing="OnItemEditing"
          ItemUpdating="OnItemUpdating"
          ItemCanceling="OnItemCanceling"
          ItemDeleting="OnItemDeleting"
          ItemInserting="OnItemInserting">
    <ItemTemplate>
        <tr>
            <td>@Item.Name</td>
            <td>
                <button @onclick="() => listView.HandleCommand("edit", null, index)">Edit</button>
                <button @onclick="() => listView.HandleCommand("delete", null, index)">Delete</button>
            </td>
        </tr>
    </ItemTemplate>
    <EditItemTemplate>
        <tr>
            <td><input @bind="editName" /></td>
            <td>
                <button @onclick="() => listView.HandleCommand("update", null, editIndex)">Update</button>
                <button @onclick="() => listView.HandleCommand("cancel", null, editIndex)">Cancel</button>
            </td>
        </tr>
    </EditItemTemplate>
    <InsertItemTemplate>
        <tr>
            <td><input @bind="newName" /></td>
            <td>
                <button @onclick="() => listView.HandleCommand("insert", null, 0)">Insert</button>
            </td>
        </tr>
    </InsertItemTemplate>
    <EmptyDataTemplate>No items available.</EmptyDataTemplate>
</ListView>
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CRUD Operations

The ListView supports full Create, Read, Update, and Delete operations through a set of command events. Use HandleCommand on the ListView reference to trigger operations.

Events

Event EventArgs Description
ItemEditing ListViewEditEventArgs Fires when an Edit command is requested. Set NewEditIndex to control which item enters edit mode.
ItemUpdating ListViewUpdateEventArgs Fires when an Update command is requested. ItemIndex identifies the item being updated.
ItemCanceling ListViewCancelEventArgs Fires when a Cancel command is requested.
ItemDeleting ListViewDeleteEventArgs Fires before an item is deleted. Set Cancel = true to prevent deletion.
ItemDeleted ListViewDeletedEventArgs Fires after a delete operation completes.
ItemInserting ListViewInsertEventArgs Fires before an item is inserted. Set Cancel = true to prevent insertion.
ItemInserted ListViewInsertedEventArgs Fires after an insert operation completes.

EditItemTemplate

When EditIndex is set to a valid item index, the EditItemTemplate is rendered for that item instead of the ItemTemplate. Set EditIndex = -1 to exit edit mode.

InsertItemTemplate

The InsertItemTemplate renders an insert row when InsertItemPosition is set to FirstItem or LastItem. Set to None (default) to hide the insert row.

Migration Example

Before (Web Forms):

<asp:ListView ID="lvItems" runat="server"
    OnItemEditing="lvItems_ItemEditing"
    OnItemUpdating="lvItems_ItemUpdating"
    OnItemDeleting="lvItems_ItemDeleting"
    OnItemInserting="lvItems_ItemInserting"
    InsertItemPosition="LastItem">
    <ItemTemplate>
        <tr>
            <td><%# Eval("Name") %></td>
            <td>
                <asp:Button runat="server" CommandName="Edit" Text="Edit" />
                <asp:Button runat="server" CommandName="Delete" Text="Delete" />
            </td>
        </tr>
    </ItemTemplate>
    <EditItemTemplate>
        <tr>
            <td><asp:TextBox ID="txtName" runat="server" Text='<%# Bind("Name") %>' /></td>
            <td>
                <asp:Button runat="server" CommandName="Update" Text="Update" />
                <asp:Button runat="server" CommandName="Cancel" Text="Cancel" />
            </td>
        </tr>
    </EditItemTemplate>
</asp:ListView>

After (Blazor):

<ListView @ref="listView" Context="Item" ItemType="Widget"
    EditIndex="@editIndex"
    InsertItemPosition="InsertItemPosition.LastItem"
    ItemEditing="OnItemEditing"
    ItemUpdating="OnItemUpdating"
    ItemDeleting="OnItemDeleting"
    ItemInserting="OnItemInserting">
    <ItemTemplate>
        <tr>
            <td>@Item.Name</td>
            <td>
                <button @onclick="() => listView.HandleCommand("edit", null, idx)">Edit</button>
                <button @onclick="() => listView.HandleCommand("delete", null, idx)">Delete</button>
            </td>
        </tr>
    </ItemTemplate>
    <EditItemTemplate>
        <tr>
            <td><input @bind="editName" /></td>
            <td>
                <button @onclick="() => listView.HandleCommand("update", null, editIndex)">Update</button>
                <button @onclick="() => listView.HandleCommand("cancel", null, editIndex)">Cancel</button>
            </td>
        </tr>
    </EditItemTemplate>
</ListView>
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