DataKeyArray.Count Property

Reference

Definition

Namespace:: System.Web.UI.WebControls

Assembly:: System.Web.dll

Important

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Gets the number of items in the collection.

public:
 property int Count { int get(); };

public int Count { get; }

member this.Count : int

Public ReadOnly Property Count As Integer

Property Value

Int32

The number of items in the collection.

Implements

Count

Examples

The following code example demonstrates how to use the Count property to determine whether a DataKeyArray collection is empty.

ASP.NET (C#)


<%@ 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">

  void CustomerGridView_DataBound(Object sender, EventArgs e)
  {

    // Use the Count property to determine whether the
    // DataKeys collection contains any items.
    if (CustomerGridView.DataKeys.Count > 0)
    {

      MessageLabel.Text = "The primary key of each record displayed are: <br/><br/>";

      // Use the GetEnumerator method to create an enumerator that 
      // contains the DataKey objects for the GridView control.
      IEnumerator keyEnumerator = CustomerGridView.DataKeys.GetEnumerator();

      // Iterate though the enumerator and display the primary key
      // value of each record displayed.
      while (keyEnumerator.MoveNext())
      {
        DataKey key = (DataKey)keyEnumerator.Current;
        MessageLabel.Text += key.Value.ToString() + "<br/>";
      }

    }
    else
    {
      MessageLabel.Text = "No DataKey objects.";
    }

  }
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >

  <head runat="server">
    <title>DataKeyArray Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DataKeyArray Example</h3>
                       
        <asp:gridview id="CustomerGridView"
          datasourceid="CustomerDataSource"
          autogeneratecolumns="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          ondatabound="CustomerGridView_DataBound" 
          runat="server">
            
        </asp:gridview>
        
        <br/>
        
        <asp:label id="MessageLabel"
          forecolor="Red"
          runat="server"/>
            
        <!-- This example uses Microsoft SQL Server and connects  -->
        <!-- to the Northwind sample database. Use an ASP.NET     -->
        <!-- expression to retrieve the connection string value   -->
        <!-- from the Web.config file.                            -->
        <asp:sqldatasource id="CustomerDataSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </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">

  Sub CustomerGridView_DataBound(ByVal sender As Object, ByVal e As EventArgs) Handles CustomerGridView.DataBound

    ' Use the Count property to determine whether the
    ' DataKeys collection contains any items.
    If CustomerGridView.DataKeys.Count > 0 Then

      MessageLabel.Text = "The primary key of each record displayed are: <br/><br/>"

      ' Use the GetEnumerator method to create an enumerator that 
      ' contains the DataKey objects for the GridView control.
      Dim keyEnumerator As IEnumerator = CustomerGridView.DataKeys.GetEnumerator()

      ' Iterate though the enumerator and display the primary key
      ' value of each record displayed.
      While keyEnumerator.MoveNext()
      
        Dim key As DataKey = CType(keyEnumerator.Current, DataKey)
        MessageLabel.Text &= key.Value.ToString() & "<br/>"
      
      End While

    Else
    
      MessageLabel.Text = "No DataKey objects."
    
    End If

  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >

  <head runat="server">
    <title>DataKeyArray Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>DataKeyArray Example</h3>
                       
        <asp:gridview id="CustomerGridView"
          datasourceid="CustomerDataSource"
          autogeneratecolumns="true"
          datakeynames="CustomerID"  
          allowpaging="true"
          runat="server">
            
        </asp:gridview>
        
        <br/>
        
        <asp:label id="MessageLabel"
          forecolor="Red"
          runat="server"/>
            
        <!-- This example uses Microsoft SQL Server and connects  -->
        <!-- to the Northwind sample database. Use an ASP.NET     -->
        <!-- expression to retrieve the connection string value   -->
        <!-- from the Web.config file.                            -->
        <asp:sqldatasource id="CustomerDataSource"
          selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
          connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>" 
          runat="server"/>
            
      </form>
  </body>
</html>

Remarks

Use the Count property to determine the number of items in the collection. The Count property is commonly used when iterating through the collection to determine its upper bound. The Count property is also commonly used to determine whether a collection is empty.

Applies to

Product	Versions
.NET Framework	2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

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