ListView.GroupItemCount Property

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.Extensions.dll

Gets or sets the number of items to display per group in a ListView control.

public:
 virtual property int GroupItemCount { int get(); void set(int value); };
public virtual int GroupItemCount { get; set; }
member this.GroupItemCount : int with get, set
Public Overridable Property GroupItemCount As Integer

Property Value

Int32

The number of items to display per group in a ListView control. The default is 1, which indicates that the ListView control will display one item per group.

Exceptions

ArgumentOutOfRangeException

The GroupItemCount property is set to a value less than 1.

Examples

The following example shows how to create a tiled layout in the ListView control by using the GroupItemCount property. It also shows how to change this property programmatically.

<%@ Page language="C#" %>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

    protected void GroupItemCountList_SelectedIndexChanged(object sender, EventArgs e)
    {
      // Changes the number of items displayed for each group.
      ContactsListView.GroupItemCount = 
        Convert.ToInt32(GroupItemCountList.SelectedValue);
    }
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView GroupItemCount Example</title>
    <style type="text/css">
      body { font: 10pt Trebuchet MS; }        
    </style>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView GroupItemCount Example</h3>

      Number of columns:
      <asp:DropDownList ID="GroupItemCountList"
        AutoPostBack="true"
        runat="server"         
        OnSelectedIndexChanged="GroupItemCountList_SelectedIndexChanged"        
        >
          <asp:ListItem>1</asp:ListItem>
          <asp:ListItem Selected="True">2</asp:ListItem>
          <asp:ListItem>3</asp:ListItem>
          <asp:ListItem>4</asp:ListItem>
      </asp:DropDownList>
      <br />
      <br />      
      <hr />
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        GroupItemCount="2"        
        runat="server">
        <LayoutTemplate>
          <table id="tblContacts" runat="server" cellspacing="0" cellpadding="2">
            <tr runat="server" id="groupPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="ContactsDataPager" PageSize="24">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|&lt;&lt; " LastPageText=" &gt;&gt;|"
                NextPageText=" &gt; " PreviousPageText=" &lt; " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <td align="center" style="width:10px" runat="server">
            <asp:Label ID="IDLabel" runat="Server" Text='<%#Eval("ContactID") %>' />
          </td>
          <td style="width:70px" runat="server">
            <asp:Label ID="FirstNameLabel" runat="Server" Text='<%#Eval("FirstName") %>' />
          </td>
          <td style="width:70px" runat="server">
            <asp:Label ID="LastNameLabel" runat="Server" Text='<%#Eval("LastName") %>' />
          </td>
        </ItemTemplate>
        <GroupTemplate>
          <tr runat="server" id="ContactsRow" style="background-color: #FFFFFF">
            <td runat="server" id="itemPlaceholder" />
          </tr>
        </GroupTemplate>
        <ItemSeparatorTemplate>
          <td runat="server" style="border-right: 1px solid #00C0C0">&nbsp;</td>
        </ItemSeparatorTemplate>
      </asp:ListView>

      <!-- This example uses Microsoft SQL Server and connects      -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET    -->
      <!-- expression to retrieve the connection string value       -->
      <!-- from the Web.config file.                                -->
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName] FROM Person.Contact">
      </asp:SqlDataSource>
      
    </form>
  </body>
</html>

<%@ Page language="VB" %>
    
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

  Protected Sub GroupItemCountList_SelectedIndexChanged(ByVal sender As Object, _
    ByVal e As EventArgs)
          
    ' Changes the number of items displayed for each group.  
    ContactsListView.GroupItemCount = _
      Convert.ToInt32(GroupItemCountList.SelectedValue)
        
  End Sub
    
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head id="Head1" runat="server">
    <title>ListView GroupItemCount Example</title>
    <style type="text/css">
      body { font: 10pt Trebuchet MS; }        
    </style>
  </head>
  <body>
    <form id="form1" runat="server">
        
      <h3>ListView GroupItemCount Example</h3>

      Number of columns:
      <asp:DropDownList ID="GroupItemCountList"
        AutoPostBack="true"
        runat="server"         
        OnSelectedIndexChanged="GroupItemCountList_SelectedIndexChanged"        
        >
          <asp:ListItem>1</asp:ListItem>
          <asp:ListItem Selected="True">2</asp:ListItem>
          <asp:ListItem>3</asp:ListItem>
          <asp:ListItem>4</asp:ListItem>
      </asp:DropDownList>
      <br />
      <br />      
      <hr />
      
      <asp:ListView ID="ContactsListView" 
        DataSourceID="ContactsDataSource" 
        GroupItemCount="2"        
        runat="server">
        <LayoutTemplate>
          <table id="tblContacts" runat="server" cellspacing="0" cellpadding="2">
            <tr runat="server" id="groupPlaceholder" />
          </table>
          <asp:DataPager runat="server" ID="ContactsDataPager" PageSize="24">
            <Fields>
              <asp:NextPreviousPagerField 
                ShowFirstPageButton="true" ShowLastPageButton="true"
                FirstPageText="|&lt;&lt; " LastPageText=" &gt;&gt;|"
                NextPageText=" &gt; " PreviousPageText=" &lt; " />
            </Fields>
          </asp:DataPager>
        </LayoutTemplate>
        <ItemTemplate>
          <td align="center" style="width:10px" runat="server">
            <asp:Label ID="IDLabel" runat="Server" Text='<%#Eval("ContactID") %>' />
          </td>
          <td style="width:70px" runat="server">
            <asp:Label ID="FirstNameLabel" runat="Server" Text='<%#Eval("FirstName") %>' />
          </td>
          <td style="width:70px" runat="server">
            <asp:Label ID="LastNameLabel" runat="Server" Text='<%#Eval("LastName") %>' />
          </td>
        </ItemTemplate>
        <GroupTemplate>
          <tr runat="server" id="ContactsRow" style="background-color: #FFFFFF">
            <td runat="server" id="itemPlaceholder" />
          </tr>
        </GroupTemplate>
        <ItemSeparatorTemplate>
          <td runat="server" style="border-right: 1px solid #00C0C0">&nbsp;</td>
        </ItemSeparatorTemplate>
      </asp:ListView>

      <!-- This example uses Microsoft SQL Server and connects      -->
      <!-- to the AdventureWorks sample database. Use an ASP.NET    -->
      <!-- expression to retrieve the connection string value       -->
      <!-- from the Web.config file.                                -->
      <asp:SqlDataSource ID="ContactsDataSource" runat="server" 
        ConnectionString="<%$ ConnectionStrings:AdventureWorks_DataConnectionString %>"
        SelectCommand="SELECT [ContactID], [FirstName], [LastName] FROM Person.Contact">
      </asp:SqlDataSource>
      
    </form>
  </body>
</html>

Remarks

Use the GroupItemCount property to specify the number of items to be grouped together in the ListView control. (In other words, this specifies the number of items to display for each group of the control.) For each group, the ListView control renders the contents of the GroupTemplate template and replaces the item placeholder with the actual item content. It does this as many times as the number of items defined by the GroupItemCount property.

You can use GroupItemCount with the GroupTemplate template to create a tiled layout in the ListView control. In a tiled table layout, the items are repeated horizontally in a row. The numbers of times that an item is repeated is specified by the GroupItemCount property.

Applies to

See also