ListView.DataKeys Property
Definition
Important
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public:
virtual property System::Web::UI::WebControls::DataKeyArray ^ DataKeys { System::Web::UI::WebControls::DataKeyArray ^ get(); };
[System.ComponentModel.Browsable(false)]
public virtual System.Web.UI.WebControls.DataKeyArray DataKeys { get; }
[<System.ComponentModel.Browsable(false)>]
member this.DataKeys : System.Web.UI.WebControls.DataKeyArray
Public Overridable ReadOnly Property DataKeys As DataKeyArray
Property Value
An object that contains the data key for each item in a ListView control.
- Attributes
Examples
The following example shows how to use the DataKeys property to determine the data-key values for the items in a ListView control. It also shows how to preserve the user selection based on a data item instead of the default behavior that uses the index.
void ContactsListView_SelectedIndexChanged(Object sender, EventArgs e)
{
if (ContactsListView.SelectedIndex >= 0)
ViewState["SelectedKey"] = ContactsListView.SelectedValue;
else
ViewState["SelectedKey"] = null;
}
void ContactsListView_DataBound(Object sender, EventArgs e)
{
for (int i = 0; i < ContactsListView.Items.Count; i++)
{
// Ignore values that cannot be cast as integer.
try
{
if ((int)ContactsListView.DataKeys[i].Value == (int)ViewState["SelectedKey"])
ContactsListView.SelectedIndex = i;
}
catch { }
}
}
Sub ContactsListView_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
If ContactsListView.SelectedIndex >= 0 Then
ViewState("SelectedKey") = ContactsListView.SelectedValue
Else
ViewState("SelectedKey") = Nothing
End If
End Sub
Sub ContactsListView_DataBound(ByVal sender As Object, ByVal e As EventArgs)
For i As Integer = 0 To ContactsListView.Items.Count - 1
' Ignore values that cannot be cast as integer.
Try
If Convert.ToInt32(ContactsListView.DataKeys(i).Value) = Convert.ToInt32(ViewState("SelectedKey")) Then _
ContactsListView.SelectedIndex = i
Catch
End Try
Next
End Sub
Remarks
When the DataKeyNames property is set, the ListView control automatically creates a DataKey object for each item in the control. The DataKey object contains the values of the field or fields that are specified in the DataKeyNames property. The DataKey objects are then added to the control's DataKeys collection.
Use the DataKeys property to retrieve the DataKey object for a specific data item in the ListView control.
You can use the SelectedDataKey property to retrieve the DataKey object for the currently selected item. You can also use the SelectedValue property to retrieve the data-key value for the currently selected item directly.
You can use the ListViewDataItem.DisplayIndex property to retrieve the DataKey object for the item for which a command button was clicked.
Applies to
See also
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