DataGridColumnCollection.Add(DataGridColumn) Méthode
Définition
Important
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Ajoute l'objet de colonne dérivé de DataGridColumn spécifié à la fin de la collection DataGridColumnCollection.
public:
void Add(System::Web::UI::WebControls::DataGridColumn ^ column);public void Add (System.Web.UI.WebControls.DataGridColumn column);member this.Add : System.Web.UI.WebControls.DataGridColumn -> unitPublic Sub Add (column As DataGridColumn)Paramètres
- column
- DataGridColumn
Objet de colonne dérivé de DataGridColumn à ajouter à DataGridColumnCollection.
Exemples
L’exemple de code suivant montre comment utiliser la Add méthode pour ajouter dynamiquement une colonne au DataGrid contrôle. Notez que la Columns propriété du contrôle est une instance de DataGrid la DataGridColumnCollection classe.
<%@ 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 < 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)
{
// Create a DataGrid control.
DataGrid ItemsGrid = new DataGrid();
// Set the properties of the DataGrid.
ItemsGrid.ID = "ItemsGrid";
ItemsGrid.BorderColor = System.Drawing.Color.Black;
ItemsGrid.CellPadding = 3;
ItemsGrid.AutoGenerateColumns = false;
// Set the styles for the DataGrid.
ItemsGrid.HeaderStyle.BackColor =
System.Drawing.Color.FromArgb(0x0000aaaa);
// Create the columns for the DataGrid control. The DataGrid
// columns are dynamically generated. Therefore, the columns
// must be re-created each time the page is refreshed.
// Create and add the columns to the collection.
ItemsGrid.Columns.Add(CreateBoundColumn("IntegerValue", "Item"));
ItemsGrid.Columns.Add(
CreateBoundColumn("StringValue", "Description"));
ItemsGrid.Columns.Add(
CreateBoundColumn("CurrencyValue", "Price", "{0:c}",
HorizontalAlign.Right));
ItemsGrid.Columns.Add(
CreateLinkColumn("http://www.microsoft.com", "_self",
"Microsoft", "Related link"));
// Specify the data source and bind it to the control.
ItemsGrid.DataSource = CreateDataSource();
ItemsGrid.DataBind();
// Add the DataGrid control to the Controls collection of
// the PlaceHolder control.
Place.Controls.Add(ItemsGrid);
}
BoundColumn CreateBoundColumn(String DataFieldValue,
String HeaderTextValue)
{
// This version of the CreateBoundColumn method sets only the
// DataField and HeaderText properties.
// Create a BoundColumn.
BoundColumn column = new BoundColumn();
// Set the properties of the BoundColumn.
column.DataField = DataFieldValue;
column.HeaderText = HeaderTextValue;
return column;
}
BoundColumn CreateBoundColumn(String DataFieldValue,
String HeaderTextValue, String FormatValue,
HorizontalAlign AlignValue)
{
// This version of CreateBoundColumn method sets the DataField,
// HeaderText, and DataFormatString properties. It also sets the
// HorizontalAlign property of the ItemStyle property of the column.
// Create a BoundColumn using the overloaded CreateBoundColumn method.
BoundColumn column = CreateBoundColumn(DataFieldValue, HeaderTextValue);
// Set the properties of the BoundColumn.
column.DataFormatString = FormatValue;
column.ItemStyle.HorizontalAlign = AlignValue;
return column;
}
HyperLinkColumn CreateLinkColumn(String NavUrlValue,
String TargetValue, String TextValue, String HeaderTextValue)
{
// Create a BoundColumn.
HyperLinkColumn column = new HyperLinkColumn();
// Set the properties of the ButtonColumn.
column.NavigateUrl = NavUrlValue;
column.Target = TargetValue;
column.Text = TextValue;
column.HeaderText = HeaderTextValue;
return column;
}
</script>
<head runat="server">
<title>DataGrid Constructor Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGrid Constructor Example</h3>
<b>Product List</b>
<asp:PlaceHolder id="Place"
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 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 DataView = New DataView(dt)
Return dv
End Function
Sub Page_Load(sender As Object, e As EventArgs)
' Create a DataGrid control.
Dim ItemsGrid As DataGrid = New DataGrid()
' Set the properties of the DataGrid.
ItemsGrid.ID = "ItemsGrid"
ItemsGrid.BorderColor = System.Drawing.Color.Black
ItemsGrid.CellPadding = 3
ItemsGrid.AutoGenerateColumns = False
' Set the styles for the DataGrid.
ItemsGrid.HeaderStyle.BackColor = System.Drawing.Color.FromArgb(&H0000aaaa)
' Create the columns for the DataGrid control. The DataGrid
' columns are dynamically generated. Therefore, the columns
' must be re-created each time the page is refreshed.
' Create and add the columns to the collection.
ItemsGrid.Columns.Add(CreateBoundColumn("IntegerValue", "Item"))
ItemsGrid.Columns.Add( _
CreateBoundColumn("StringValue", "Description"))
ItemsGrid.Columns.Add( _
CreateBoundColumn("CurrencyValue", "Price", "{0:c}", _
HorizontalAlign.Right))
ItemsGrid.Columns.Add( _
CreateLinkColumn("http:'www.microsoft.com", "_self", _
"Microsoft", "Related link"))
' Specify the data source and bind it to the control.
ItemsGrid.DataSource = CreateDataSource()
ItemsGrid.DataBind()
' Add the DataGrid control to the Controls collection of
' the PlaceHolder control.
Place.Controls.Add(ItemsGrid)
End Sub
Function CreateBoundColumn(DataFieldValue As String, HeaderTextValue As String) As BoundColumn
' This version of CreateBoundColumn method sets only the
' DataField and HeaderText properties.
' Create a BoundColumn.
Dim column As BoundColumn = New BoundColumn()
' Set the properties of the BoundColumn.
column.DataField = DataFieldValue
column.HeaderText = HeaderTextValue
Return column
End Function
Function CreateBoundColumn(DataFieldValue As String, _
HeaderTextValue As String, FormatValue As String, _
AlignValue As HorizontalAlign) As BoundColumn
' This version of CreateBoundColumn method sets the DataField,
' HeaderText, and DataFormatString properties. It also sets the
' HorizontalAlign property of the ItemStyle property of the column.
' Create a BoundColumn using the overloaded CreateBoundColumn method.
Dim column As BoundColumn = CreateBoundColumn(DataFieldValue, HeaderTextValue)
' Set the properties of the BoundColumn.
column.DataFormatString = FormatValue
column.ItemStyle.HorizontalAlign = AlignValue
Return column
End Function
Function CreateLinkColumn(NavUrlValue As String, TargetValue As String, _
TextValue As String, HeaderTextValue As String) As HyperLinkColumn
' Create a BoundColumn.
Dim column As HyperLinkColumn = New HyperLinkColumn()
' Set the properties of the ButtonColumn.
column.NavigateUrl = NavUrlValue
column.Target = TargetValue
column.Text = TextValue
column.HeaderText = HeaderTextValue
Return column
End Function
</script>
<head runat="server">
<title>DataGrid Constructor Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGrid Constructor Example</h3>
<b>Product List</b>
<asp:PlaceHolder id="Place"
runat="server"/>
</form>
</body>
</html>
Remarques
Utilisez cette méthode pour ajouter un DataGridColumnobjet de colonne dérivé à la fin d’une DataGridColumnCollection collection.
Le DataGrid contrôle ne stocke pas le contenu de sa Columns collection dans l’état d’affichage. Pour ajouter ou supprimer une colonne dynamiquement, vous devez ajouter ou supprimer la colonne par programmation chaque fois que la page est actualisée. Fournissez une Page_Init fonction qui ajoute ou supprime la colonne avant que le DataGrid contrôle puisse recharger son état et se reconstruire. Sinon, les modifications apportées à la Columns collection ne sont pas reflétées dans le DataGrid contrôle lorsqu’elle est affichée.
Notes
Bien que vous puissiez ajouter par programmation des colonnes à ou supprimer des colonnes de la Columns collection du DataGrid contrôle, il est plus facile de répertorier les colonnes statiquement, puis d’utiliser la Visible propriété pour afficher ou masquer chaque colonne.