DataGrid.Columns Właściwość

  • Odwołanie

Definicja

Przestrzeń nazw:
System.Web.UI.WebControls
Zestaw:
System.Web.dll

Pobiera kolekcję obiektów reprezentujących kolumny kontrolki DataGrid .

public:
 virtual property System::Web::UI::WebControls::DataGridColumnCollection ^ Columns { System::Web::UI::WebControls::DataGridColumnCollection ^ get(); };
[System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)]
public virtual System.Web.UI.WebControls.DataGridColumnCollection Columns { get; }
[<System.Web.UI.PersistenceMode(System.Web.UI.PersistenceMode.InnerProperty)>]
member this.Columns : System.Web.UI.WebControls.DataGridColumnCollection
Public Overridable ReadOnly Property Columns As DataGridColumnCollection

Wartość właściwości

DataGridColumnCollection

DataGridColumnCollection Obiekt zawierający kolekcję obiektów reprezentujących kolumny kontrolkiDataGrid.

Atrybuty
PersistenceModeAttribute

Przykłady

Poniższy przykład kodu przedstawia sposób dynamicznego dodawania kolumny do kontrolki DataGrid za Columns pomocą kolekcji.

<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <script language="C#" runat="server">
 
      DataTable Cart;
      DataView CartView;
 
      ICollection CreateDataSource() 
      {
         DataTable dt = new DataTable();
         DataRow dr;
 
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
 
         for (int i = 0; i < 9; i++) 
         {
            dr = dt.NewRow();
   
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         DataView dv = new DataView(dt);
         return dv;
      } 
 
      void Page_Load(Object sender, EventArgs e) 
      {

         if (Session["DG4_ShoppingCart"] == null) 
         {
            Cart = new DataTable();
            Cart.Columns.Add(new DataColumn("Item", typeof(string)));
            Cart.Columns.Add(new DataColumn("Price", typeof(string)));
            Session["DG4_ShoppingCart"] = Cart;
         }
         else 
         {
            Cart = (DataTable)Session["DG4_ShoppingCart"];
         }    
         CartView = new DataView(Cart);
         ShoppingCart.DataSource = CartView;
         ShoppingCart.DataBind();
 
         if (!IsPostBack) 
         {
            // Load this data only once.
            ItemsGrid.DataSource= CreateDataSource();
            ItemsGrid.DataBind();
         }

      }

      void Page_Init(Object sender, EventArgs e) 
      {

         // Create a dynamic column to add to Columns collection.
         BoundColumn NumberColumn = new BoundColumn();
         NumberColumn.HeaderText="Item Number"; 
         NumberColumn.DataField="IntegerValue";

         // Add column to Columns collection.
         ItemsGrid.Columns.AddAt(2, NumberColumn);

      }
  
      void Grid_CartCommand(Object sender, DataGridCommandEventArgs e) {
     
         DataRow dr = Cart.NewRow();
          
         // e.Item is the table row where the command is raised.
         // For bound columns, the value is stored in the Text property of the TableCell.
         TableCell itemCell = e.Item.Cells[2];
         TableCell priceCell = e.Item.Cells[3];
         string item = itemCell.Text;
         string price = priceCell.Text;
         
         if (((Button)e.CommandSource).CommandName == "AddToCart") 
         {
            dr[0] = item;
            dr[1] = price;
            Cart.Rows.Add(dr);
         }
         else 
         { 

            //Remove from Cart.
         
            CartView.RowFilter = "Item='" + item + "'";
            if (CartView.Count > 0) 
            {    
               CartView.Delete(0);
            }
            CartView.RowFilter = "";
         }
         ShoppingCart.DataBind();
 
      }
 
   </script>
 
<head runat="server">
    <title>DataGrid Columns Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>DataGrid Columns Example</h3>
 
      <table cellpadding="5">
         <tr valign="top">
            <td>
 
               <b>Product List</b>
 
               <asp:DataGrid id="ItemsGrid"
                    BorderColor="black"
                    BorderWidth="1"
                    CellPadding="3"
                    AutoGenerateColumns="false"
                    OnItemCommand="Grid_CartCommand"
                    runat="server">

                  <HeaderStyle BackColor="#00aaaa">
                  </HeaderStyle>
 
                  <Columns>
 
                     <asp:ButtonColumn 
                          HeaderText="Add to cart" 
                          ButtonType="PushButton" 
                          Text="Add" 
                          CommandName="AddToCart"/>
 
                     <asp:ButtonColumn 
                          HeaderText="Remove from cart" 
                          ButtonType="PushButton" 
                          Text="Remove" 
                          CommandName="RemoveFromCart"/>
 
                     <asp:BoundColumn 
                          HeaderText="Item" 
                          DataField="StringValue"/>
 
                     <asp:BoundColumn 
                          HeaderText="Price" 
                          DataField="CurrencyValue" 
                          DataFormatString="{0:c}">

                        <ItemStyle HorizontalAlign="right">
                        </ItemStyle>

                     </asp:BoundColumn>
 
                  </Columns>
   
               </asp:DataGrid>
 
            </td>
            <td>
 
               <b>Shopping Cart</b>
 
               <asp:DataGrid id="ShoppingCart" 
                    runat="server"
                    BorderColor="black"
                    BorderWidth="1"
                    GridLines="Both"
                    ShowFooter="false"
                    CellPadding="3"
                    CellSpacing="0">

                  <HeaderStyle BackColor="#00aaaa">
                  </HeaderStyle>

                </asp:DataGrid>
 
            </td>
         </tr>
 
      </table>
 
   </form>
 
</body>
</html>

<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <script language="VB" runat="server">
    Dim Cart As DataTable
    Dim CartView As DataView
    
    Function CreateDataSource() As ICollection
        Dim dt As New DataTable()
        Dim dr As DataRow
        
        dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
        dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
        dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))
        
        Dim i As Integer
        For i = 0 To 8
            dr = dt.NewRow()
            
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 *(i + 1)
            
            dt.Rows.Add(dr)
        Next i
        
        Dim dv As New DataView(dt)
        Return dv
    End Function 'CreateDataSource


    Sub Page_Load(sender As Object, e As EventArgs)
        
        If Session("DG4_ShoppingCart") Is Nothing Then
            Cart = New DataTable()
            Cart.Columns.Add(New DataColumn("Item", GetType(String)))
            Cart.Columns.Add(New DataColumn("Price", GetType(String)))
            Session("DG4_ShoppingCart") = Cart
        Else
            Cart = CType(Session("DG4_ShoppingCart"), DataTable)
        End If
        CartView = New DataView(Cart)
        ShoppingCart.DataSource = CartView
        ShoppingCart.DataBind()
        
        If Not IsPostBack Then
            ' Load this data only once.
            ItemsGrid.DataSource = CreateDataSource()
            ItemsGrid.DataBind()
        End If
    End Sub 'Page_Load
     

    Sub Page_Init(sender As Object, e As EventArgs)
        
        ' Create a dynamic column to add to Columns collection.
        Dim NumberColumn As New BoundColumn()
        NumberColumn.HeaderText = "Item Number"
        NumberColumn.DataField = "IntegerValue"
        
        ' Add column to Columns collection.
        ItemsGrid.Columns.AddAt(2, NumberColumn)
    End Sub 'Page_Init
     

    Sub Grid_CartCommand(sender As Object, e As DataGridCommandEventArgs)
        
        Dim dr As DataRow = Cart.NewRow()
        
        ' e.Item is the table row where the command is raised.
        ' For bound columns, the value is stored in the Text property of the TableCell.
        Dim itemCell As TableCell = e.Item.Cells(2)
        Dim priceCell As TableCell = e.Item.Cells(3)
        Dim item As String = itemCell.Text
        Dim price As String = priceCell.Text
        
        If CType(e.CommandSource, Button).CommandName = "AddToCart" Then
            dr(0) = item
            dr(1) = price
            Cart.Rows.Add(dr)
        Else 

            'Remove from Cart.
            CartView.RowFilter = "Item='" & item & "'"
            If CartView.Count > 0 Then
                CartView.Delete(0)
            End If
            CartView.RowFilter = ""
        End If
        ShoppingCart.DataBind()
    End Sub 'Grid_CartCommand 
     
   </script>
 
<head runat="server">
    <title>DataGrid Columns Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>DataGrid Columns Example</h3>
 
      <table cellpadding="5">
         <tr valign="top">
            <td>
 
               <b>Product List</b>
 
               <asp:DataGrid id="ItemsGrid"
                    BorderColor="black"
                    BorderWidth="1"
                    CellPadding="3"
                    AutoGenerateColumns="false"
                    OnItemCommand="Grid_CartCommand"
                    runat="server">

                  <HeaderStyle BackColor="#00aaaa">
                  </HeaderStyle>
 
                  <Columns>
 
                     <asp:ButtonColumn 
                          HeaderText="Add to cart" 
                          ButtonType="PushButton" 
                          Text="Add" 
                          CommandName="AddToCart"/>
 
                     <asp:ButtonColumn 
                          HeaderText="Remove from cart" 
                          ButtonType="PushButton" 
                          Text="Remove" 
                          CommandName="RemoveFromCart"/>
 
                     <asp:BoundColumn 
                          HeaderText="Item" 
                          DataField="StringValue"/>
 
                     <asp:BoundColumn 
                          HeaderText="Price" 
                          DataField="CurrencyValue" 
                          DataFormatString="{0:c}">

                        <ItemStyle HorizontalAlign="right">
                        </ItemStyle>

                     </asp:BoundColumn>
 
                  </Columns>
   
               </asp:DataGrid>
 
            </td>
            <td>
 
               <b>Shopping Cart</b>
 
               <asp:DataGrid id="ShoppingCart" 
                    runat="server"
                    BorderColor="black"
                    BorderWidth="1"
                    GridLines="Both"
                    ShowFooter="false"
                    CellPadding="3"
                    CellSpacing="0">

                  <HeaderStyle BackColor="#00aaaa">
                  </HeaderStyle>

                </asp:DataGrid>
 
            </td>
         </tr>
 
      </table>
 
   </form>
 
</body>
</html>


<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <script runat="server">
 
      ICollection CreateDataSource() 
      {
      
         // Create sample data for the DataGrid control.
         DataTable dt = new DataTable();
         DataRow dr;
 
         // Define the columns of the table.
         dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
         dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
         dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));
 
         // Populate the table with sample values.
         for (int i = 0; i < 5; i++) 
         {
            dr = dt.NewRow();
 
            dr[0] = i;
            dr[1] = "Item " + i.ToString();
            dr[2] = 1.23 * (i + 1);
 
            dt.Rows.Add(dr);
         }
 
         DataView dv = new DataView(dt);
         return dv;
      }
 
      void Page_Load(Object sender, EventArgs e) 
      {
 
         // Load sample data only once, when the page is first loaded.
         if (!IsPostBack) 
         {
            ItemsGrid.DataSource = CreateDataSource();
            ItemsGrid.DataBind();
         }

      }

      void Button_Click(Object sender, EventArgs e) 
      {

         // Count the number of selected items in the DataGrid control.
         int count = 0;

         // Display the selected times.
         Message.Text = "You Selected: <br />";

         // Iterate through each item (row) in the DataGrid control and
         // determine whether it is selected.
         foreach (DataGridItem item in ItemsGrid.Items)
         {

            DetermineSelection(item, ref count);        

         }

         // If no items are selected, display the appropriate message.
         if (count == 0)
         {

            Message.Text = "No items selected";

         }

      }

      void DetermineSelection(DataGridItem item, ref int count)
      {

         // Retrieve the SelectCheckBox CheckBox control from the 
         // specified item (row) in the DataGrid control.
         CheckBox selection = (CheckBox)item.FindControl("SelectCheckBox");

         // If the item is selected, display the appropriate message and
         // increment the count of selected items.
         if (selection != null)
         {

           if (selection.Checked)
           {
              Message.Text += "- " + item.Cells[1].Text + "<br />";
              count++;
           }

         }    

      }

      void Check_Change(Object sender, EventArgs e)
      {

         // Show or hide the first column depending on the value of
         // the check box.
         if (ShowCheckBox.Checked)
         {
            ItemsGrid.Columns[0].Visible = true;
         }
         else
         {
            ItemsGrid.Columns[0].Visible = false;
         }

      }

   </script>
 
<head runat="server">
    <title>DataGridColumn Visible Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>DataGridColumn Visible Example</h3>

      Select whether to show or hide the first column.

      <br /><br />
 
      <b>Product List</b>
 
      <asp:DataGrid id="ItemsGrid"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="True"
           AutoGenerateColumns="False"
           runat="server">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>

         <Columns>

            <asp:BoundColumn DataField="IntegerValue"
                 Visible="True" 
                 HeaderText="Item"/>

            <asp:BoundColumn DataField="StringValue"
                 Visible="True"  
                 HeaderText="Description"/>

            <asp:BoundColumn DataField="CurrencyValue"
                 Visible="True"  
                 HeaderText="Price"
                 DataFormatString="{0:c}">

               <ItemStyle HorizontalAlign="Right">
               </ItemStyle>

            </asp:BoundColumn>

            <asp:TemplateColumn HeaderText="Select Item"
                 Visible="True" >

               <ItemTemplate>

                  <asp:CheckBox id="SelectCheckBox"
                       Text="Add to Cart"
                       Checked="False"
                       runat="server"/>

               </ItemTemplate>

            </asp:TemplateColumn>
 
         </Columns>  
 
      </asp:DataGrid>

      <br /><br />

      <asp:Button id="SubmitButton"
           Text="Submit"
           OnClick = "Button_Click"
           runat="server"/>

      <br /><br />

      <asp:Label id="Message"
           runat="server"/>

      <hr />

      <asp:CheckBox id="ShowCheckBox"
           Text="Show first column"
           AutoPostBack="True"
           OnCheckedChanged="Check_Change"
           Checked="True"
           runat="server"/>
 
   </form>
 
</body>
</html>


<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>
 
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
   <script runat="server">
 
      Function CreateDataSource() As ICollection 
      
         ' Create sample data for the DataGrid control.
         Dim dt As DataTable = New DataTable()
         Dim dr As DataRow
 
         ' Define the columns of the table.
         dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
         dt.Columns.Add(New DataColumn("StringValue", GetType(string)))
         dt.Columns.Add(New DataColumn("CurrencyValue", GetType(double)))
 
         ' Populate the table with sample values.
         Dim i As Integer

         For i = 0 to 4 
        
            dr = dt.NewRow()
 
            dr(0) = i
            dr(1) = "Item " & i.ToString()
            dr(2) = 1.23 * (i + 1)
 
            dt.Rows.Add(dr)

         Next i
 
         Dim dv As DataView = New DataView(dt)
         Return dv

      End Function
 
      Sub Page_Load(sender As Object, e As EventArgs) 
 
         ' Load sample data only once, when the page is first loaded.
         If Not IsPostBack Then 
  
            ItemsGrid.DataSource = CreateDataSource()
            ItemsGrid.DataBind()

         End If

      End Sub

      Sub Button_Click(sender As Object, e As EventArgs) 

         ' Count the number of selected items in the DataGrid control.
         Dim count As Integer = 0

         ' Display the selected times.
         Message.Text = "You Selected: <br />"

         ' Iterate through each item (row) in the DataGrid control and
         ' determine whether it is selected.
         Dim item As DataGridItem
 
         For Each item In ItemsGrid.Items

            DetermineSelection(item, count)        

         Next

         ' If no items are selected, display the appropriate message.
         If count = 0 Then

            Message.Text = "No items selected"

         End If

      End Sub

      Sub DetermineSelection(item As DataGridItem, ByRef count As Integer)

         ' Retrieve the SelectCheckBox CheckBox control from the 
         ' specified item (row) in the DataGrid control.
         Dim selection As CheckBox = _
             CType(item.FindControl("SelectCheckBox"), CheckBox)

         ' If the item is selected, display the appropriate message and
         ' increment the count of selected items.
         If Not selection Is Nothing Then

           If selection.Checked Then
           
              Message.Text &= "- " & item.Cells(1).Text & "<br />"
              count = count + 1
           
           End If

         End If    

      End Sub

      Sub Check_Change(sender As Object, e As EventArgs)

         ' Show or hide the first column depending on the value of
         ' the check box.
         If ShowCheckBox.Checked Then
        
            ItemsGrid.Columns(0).Visible = True
         
         Else
         
            ItemsGrid.Columns(0).Visible = False
         
         End If

      End Sub

   </script>
 
<head runat="server">
    <title>DataGridColumn Visible Example</title>
</head>
<body>
 
   <form id="form1" runat="server">
 
      <h3>DataGridColumn Visible Example</h3>

      Select whether to show or hide the first column.

      <br /><br />
 
      <b>Product List</b>
 
      <asp:DataGrid id="ItemsGrid"
           BorderColor="black"
           BorderWidth="1"
           CellPadding="3"
           ShowFooter="True"
           AutoGenerateColumns="False"
           runat="server">

         <HeaderStyle BackColor="#00aaaa">
         </HeaderStyle>

         <FooterStyle BackColor="#00aaaa">
         </FooterStyle>

         <Columns>

            <asp:BoundColumn DataField="IntegerValue"
                 Visible="True" 
                 HeaderText="Item"/>

            <asp:BoundColumn DataField="StringValue"
                 Visible="True"  
                 HeaderText="Description"/>

            <asp:BoundColumn DataField="CurrencyValue"
                 Visible="True"  
                 HeaderText="Price"
                 DataFormatString="{0:c}">

               <ItemStyle HorizontalAlign="Right">
               </ItemStyle>

            </asp:BoundColumn>

            <asp:TemplateColumn HeaderText="Select Item"
                 Visible="True" >

               <ItemTemplate>

                  <asp:CheckBox id="SelectCheckBox"
                       Text="Add to Cart"
                       Checked="False"
                       runat="server"/>

               </ItemTemplate>

            </asp:TemplateColumn>
 
         </Columns> 
 
      </asp:DataGrid>

      <br /><br />

      <asp:Button id="SubmitButton"
           Text="Submit"
           OnClick = "Button_Click"
           runat="server"/>

      <br /><br />

      <asp:Label id="Message"
           runat="server"/>

      <hr />

      <asp:CheckBox id="ShowCheckBox"
           Text="Show first column"
           AutoPostBack="True"
           OnCheckedChanged="Check_Change"
           Checked="True"
           runat="server"/>
 
   </form>
 
</body>
</html>

Uwagi

Ta właściwość służy do programowego sterowania kolekcją kolumn w kontrolce DataGrid . Kolekcja Columns zawiera jawnie zadeklarowane kolumny renderowane w kontrolce DataGrid .

Uwaga

Jawnie zadeklarowane kolumny mogą być używane w połączeniu z automatycznie wygenerowanymi kolumnami. W przypadku korzystania z obu kolumn jawnie zadeklarowane zostaną najpierw renderowane, a następnie automatycznie wygenerowane kolumny. Automatycznie wygenerowane kolumny nie są dodawane do kolekcji Columns .

Kolejność wyświetlania kolumn w kontrolce DataGrid jest kontrolowana przez kolejność wyświetlania kolumn w kolekcji Columns .

W poniższej tabeli przedstawiono różne klasy kolumn, które pochodzą z DataGridColumn klasy i mogą być używane w kolekcji Columns .

Typ kolumny Opis
BoundColumn Wyświetla kolumnę powiązaną z polem w źródle danych. Wyświetla on każdy element w polu jako tekst. Jest to domyślny typ kolumny kontrolki DataGrid .
ButtonColumn Wyświetla przycisk polecenia dla każdego elementu w kolumnie. Umożliwia to utworzenie kolumny kontrolek przycisków niestandardowych, takich jak Add przycisk lub Remove .
EditCommandColumn Wyświetla kolumnę zawierającą polecenia edycji dla każdego elementu w kolumnie.
HyperLinkColumn Wyświetla zawartość każdego elementu w kolumnie jako hiperłącze. Zawartość kolumny może być powiązana z polem w źródle danych lub tekstem statycznym.
TemplateColumn Wyświetla każdy element w kolumnie po określonym szablonie. Dzięki temu można podać niestandardowe kontrolki w kolumnie.

Uwaga

Mimo że można programowo dodawać kolumny do Columns kolekcji, łatwiej jest wyświetlić kolumny statycznie, a następnie użyć Visible właściwości do pokazania lub ukrycia kolumny.

Dotyczy

Zobacz też