GridViewRow.DataItem Vlastnost

  • Reference

Definice

Obor názvů:
System.Web.UI.WebControls
Sestavení:
System.Web.dll

Získá podkladový datový objekt, ke kterému GridViewRow je objekt vázán.

public:
 virtual property System::Object ^ DataItem { System::Object ^ get(); void set(System::Object ^ value); };
public virtual object DataItem { get; set; }
member this.DataItem : obj with get, set
Public Overridable Property DataItem As Object

Hodnota vlastnosti

Object

Představuje Object podkladový datový objekt, ke kterému GridViewRow je objekt vázán.

Příklady

Následující příklad ukazuje, jak použít DataItem vlastnost k načtení hodnoty pole. Hodnota se pak použije k předběžnému výběru položky v ovládacím prvku, který DropDownList se zobrazí, když je řádek v režimu úprav.


<%@ Page language="C#" %>
<%@ import namespace="System.Data" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
  
  void AuthorsGridView_RowDataBound (Object sender, GridViewRowEventArgs e)
  {
    // Check for a row in edit mode.
    if(e.Row.RowState == DataControlRowState.Edit)
    {
      // Preselect the DropDownList control with the state value
      // for the current row.
      
      // Retrieve the underlying data item. In this example
      // the underlying data item is a DataRowView object. 
      DataRowView rowView = (DataRowView)e.Row.DataItem;
      
      // Retrieve the state value for the current row. 
      String state = rowView["state"].ToString();
      
      // Retrieve the DropDownList control from the current row. 
      DropDownList list = (DropDownList)e.Row.FindControl("StatesList");
      
      // Find the ListItem object in the DropDownList control with the 
      // state value and select the item.
      ListItem item = list.Items.FindByText(state);
      list.SelectedIndex = list.Items.IndexOf(item);
    }
  }
  
  void AuthorsGridView_RowUpdating(Object sender, GridViewUpdateEventArgs e)
  {
    // Retrieve the row being edited.
    GridViewRow row = AuthorsGridView.Rows[AuthorsGridView.EditIndex];
    
    // Retrieve the DropDownList control from the row.
    DropDownList list = (DropDownList)row.FindControl("StatesList");
    
    // Add the selected value of the DropDownList control to 
    // the NewValues collection. The NewValues collection is
    // passed to the data source control, which then updates the 
    // data source.
    e.NewValues["state"] = list.SelectedValue;
  }
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewRow DataItem Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewRow DataItem Example</h3>

      <asp:gridview id="AuthorsGridView" 
        datasourceid="AuthorsSqlDataSource" 
        autogeneratecolumns="false"
        autogenerateeditbutton="true" 
        datakeynames="au_id"
        onrowdatabound="AuthorsGridView_RowDataBound"
        onrowupdating="AuthorsGridView_RowUpdating"   
        runat="server"> 
               
        <columns>
          <asp:boundfield datafield="au_lname"
            headertext="Last Name"/>
          <asp:boundfield datafield="au_fname"
            headertext="First Name"/>
          <asp:templatefield headertext="State">
            <itemtemplate>
              <%#Eval("state")%>
            </itemtemplate>
            <edititemtemplate>
              <asp:dropdownlist id="StatesList"
                datasourceid="StatesSqlDataSource"
                datatextfield="state"  
                runat="server"/>  
              <asp:sqldatasource id="StatesSqlDataSource"  
                selectcommand="SELECT Distinct [state] FROM [authors]"
                connectionstring="server=localhost;database=pubs;integrated security=SSPI"
                runat="server">
              </asp:sqldatasource>
            </edititemtemplate>            
          </asp:templatefield>
        </columns>
                              
      </asp:gridview>
            
      <!-- This example uses Microsoft SQL Server and connects -->
      <!-- to the Pubs sample database.                        -->
      <asp:sqldatasource id="AuthorsSqlDataSource"  
        selectcommand="SELECT [au_id], [au_lname], [au_fname], [state] FROM [authors]"
        updatecommand="UPDATE authors SET [au_lname]=@au_lname, [au_fname]=@au_fname, [state]=@state WHERE au_id=@au_id"
        connectionstring="server=localhost;database=pubs;integrated security=SSPI"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>


<%@ Page language="VB" %>
<%@ import namespace="System.Data" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
  
  Sub AuthorsGridView_RowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)

    ' Check for a row in edit mode.
    If e.Row.RowState = DataControlRowState.Edit Then
    
      ' Preselect the DropDownList control with the state value
      ' for the current row.
      
      ' Retrieve the underlying data item. In this example
      ' the underlying data item is a DataRowView object. 
      Dim rowView As DataRowView = CType(e.Row.DataItem, DataRowView)
      
      ' Retrieve the state value for the current row. 
      Dim state As String = rowView("state").ToString()
      
      ' Retrieve the DropDownList control from the current row. 
      Dim list As DropDownList = CType(e.Row.FindControl("StatesList"), DropDownList)
      
      ' Find the ListItem object in the DropDownList control with the 
      ' state value and select the item.
      Dim item As ListItem = list.Items.FindByText(state)
      list.SelectedIndex = list.Items.IndexOf(item)
      
    End If
    
  End Sub
  
  Sub AuthorsGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)

    ' Retrieve the row being edited.
    Dim row As GridViewRow = AuthorsGridView.Rows(AuthorsGridView.EditIndex)
    
    ' Retrieve the DropDownList control from the row.
    Dim list As DropDownList = CType(row.FindControl("StatesList"), DropDownList)
    
    ' Add the selected value of the DropDownList control to 
    ' the NewValues collection. The NewValues collection is
    ' passed to the data source control, which then updates the 
    ' data source.
    e.NewValues("state") = list.SelectedValue
  
  End Sub
  
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>GridViewRow DataItem Example</title>
</head>
<body>
    <form id="form1" runat="server">
        
      <h3>GridViewRow DataItem Example</h3>

      <asp:gridview id="AuthorsGridView" 
        datasourceid="AuthorsSqlDataSource" 
        autogeneratecolumns="false"
        autogenerateeditbutton="true" 
        datakeynames="au_id"
        onrowdatabound="AuthorsGridView_RowDataBound"
        onrowupdating="AuthorsGridView_RowUpdating"   
        runat="server"> 
               
        <columns>
          <asp:boundfield datafield="au_lname"
            headertext="Last Name"/>
          <asp:boundfield datafield="au_fname"
            headertext="First Name"/>
          <asp:templatefield headertext="State">
            <itemtemplate>
              <%#Eval("state")%>
            </itemtemplate>
            <edititemtemplate>
              <asp:dropdownlist id="StatesList"
                datasourceid="StatesSqlDataSource"
                datatextfield="state"  
                runat="server"/>  
              <asp:sqldatasource id="StatesSqlDataSource"  
                selectcommand="SELECT Distinct [state] FROM [authors]"
                connectionstring="server=localhost;database=pubs;integrated security=SSPI"
                runat="server">
              </asp:sqldatasource>
            </edititemtemplate>            
          </asp:templatefield>
        </columns>
                              
      </asp:gridview>
            
      <!-- This example uses Microsoft SQL Server and connects -->
      <!-- to the Pubs sample database.                        -->
      <asp:sqldatasource id="AuthorsSqlDataSource"  
        selectcommand="SELECT [au_id], [au_lname], [au_fname], [state] FROM [authors]"
        updatecommand="UPDATE authors SET [au_lname]=@au_lname, [au_fname]=@au_fname, [state]=@state WHERE au_id=@au_id"
        connectionstring="server=localhost;database=pubs;integrated security=SSPI"
        runat="server">
      </asp:sqldatasource>
            
    </form>
  </body>
</html>

Poznámky

DataItem Vlastnost použijte pro přístup k vlastnostem podkladového datového objektu, ke kterému GridViewRow je objekt vázán. Vlastnost DataItem je k dispozici pouze během a po RowDataBound události ovládacího prvku GridView .

Poznámka

Tato vlastnost se vztahuje pouze na řádky dat.

Platí pro

Viz také