DataGridColumn.HeaderText Proprietà
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Ottiene o imposta il testo visualizzato nella sezione di intestazione della colonna.
public:
virtual property System::String ^ HeaderText { System::String ^ get(); void set(System::String ^ value); };public virtual string HeaderText { get; set; }member this.HeaderText : string with get, setPublic Overridable Property HeaderText As StringValore della proprietà
Testo visualizzato nella sezione di intestazione della colonna. Il valore predefinito è Empty.
Esempio
Nell'esempio di codice seguente viene illustrato come utilizzare la HeaderText proprietà per specificare il testo per la sezione di intestazione della colonna.
<%@ 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)));
dt.Columns.Add(new DataColumn("BooleanValue", typeof(bool)));
// 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);
dr[3] = false;
dt.Rows.Add(dr);
}
// To persist the data source between posts to the server, store
// it in session state.
Session["Source"] = dt;
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)
{
// Make sure to set the header text before binding the data to
// the DataGrid control; otherwise, the change will not appear
// until the next time the page is refreshed.
ItemsGrid.Columns[0].HeaderText = "Item";
ItemsGrid.DataSource = CreateDataSource();
ItemsGrid.DataBind();
}
}
void Button_Click(Object sender, EventArgs e)
{
double subtotal = 0.0;
// Update the data source with the user's selection and
// calculate the subtotal.
DataTable dt = UpdateSource(ref subtotal);
// Display the subtotal in the footer section of the third column.
ItemsGrid.Columns[2].FooterText =
"Subtotal: " + subtotal.ToString("c");
// Create a DataView and bind it to the DataGrid control.
DataView dv = new DataView(dt);
ItemsGrid.DataSource = dv;
ItemsGrid.DataBind();
}
DataTable UpdateSource(ref double subtotal)
{
// Retrieve the data table from session state.
DataTable dt = (DataTable)Session["Source"];
// Iterate through the Items collection and update the data source
// with the user's selections. If an item is selected, add the
// amount of the item to the subtotal.
foreach (DataGridItem item in ItemsGrid.Items)
{
// Retrieve the SelectCheckBox CheckBox control from the
// specified item (row) in the DataGrid control.
CheckBox selection = (CheckBox)item.FindControl("SelectCheckBox");
if (selection != null)
{
// Update the BooleanValue field with the value of the check box.
dt.Rows[item.ItemIndex][3] = selection.Checked;
// Add the value of the item to the subtotal if the item is
// selected.
if (selection.Checked)
{
subtotal +=
Convert.ToDouble(item.Cells[2].Text.Substring(1));
}
}
}
// Save the data source.
Session["Source"] = dt;
return dt;
}
</script>
<head runat="server">
<title>DataGridColumn HeaderText and FooterText Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGridColumn HeaderText and FooterText Example</h3>
<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"/>
<asp:BoundColumn DataField="StringValue"
HeaderText="Description"/>
<asp:BoundColumn DataField="CurrencyValue"
HeaderText="Price"
DataFormatString="{0:c}">
<ItemStyle HorizontalAlign="Right">
</ItemStyle>
</asp:BoundColumn>
<asp:TemplateColumn HeaderText="Select Item">
<ItemTemplate>
<asp:CheckBox id="SelectCheckBox"
Text="Add to Cart"
Checked='<%# DataBinder.Eval(Container.DataItem, "BooleanValue") %>'
runat="server"/>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>
<br /><br />
<asp:Button id="SubmitButton"
Text="Submit"
OnClick = "Button_Click"
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)))
dt.Columns.Add(new DataColumn("BooleanValue", GetType(Boolean)))
' 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)
dr(3) = False
dt.Rows.Add(dr)
Next i
' To persist the data source between posts to the server, store
' it in session state.
Session("Source") = dt
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
' Make sure to set the header text before binding the data to
' the DataGrid control; otherwise, the change will not appear
' until the next time the page is refreshed.
ItemsGrid.Columns(0).HeaderText = "Item"
ItemsGrid.DataSource = CreateDataSource()
ItemsGrid.DataBind()
End If
End Sub
Sub Button_Click(sender As Object, e As EventArgs)
Dim subtotal As Double = 0.0
' Update the data source with the user's selection and
' calculate the subtotal.
Dim dt As DataTable = UpdateSource(subtotal)
' Display the subtotal in the footer section of the third column.
ItemsGrid.Columns(2).FooterText = _
"Subtotal: " & subtotal.ToString("c")
' Create a DataView and bind it to the DataGrid control.
Dim dv As DataView = New DataView(dt)
ItemsGrid.DataSource = dv
ItemsGrid.DataBind()
End Sub
Function UpdateSource(ByRef subtotal As Double) As DataTable
' Retrieve the data table from session state.
Dim dt As DataTable = CType(Session("Source"), DataTable)
Dim item As DataGridItem
' Iterate through the Items collection and update the data source
' with the user's selections. If an item is selected, add the
' amount of the item to the subtotal.
For Each item in ItemsGrid.Items
' Retrieve the SelectCheckBox CheckBox control from the
' specified item (row) in the DataGrid control.
Dim selection As CheckBox = _
CType(item.FindControl("SelectCheckBox"), CheckBox)
If Not selection Is Nothing
' Update the BooleanValue field with the value of the check box.
dt.Rows(item.ItemIndex)(3) = selection.Checked
' Add the value of the item to the subtotal if the item is
' selected.
If selection.Checked Then
subtotal += _
Convert.ToDouble(item.Cells(2).Text.Substring(1))
End If
End If
Next
' Save the data source.
Session("Source") = dt
Return dt
End Function
</script>
<head runat="server">
<title>DataGridColumn HeaderText and FooterText Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGridColumn HeaderText and FooterText Example</h3>
<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"/>
<asp:BoundColumn DataField="StringValue"
HeaderText="Description"/>
<asp:BoundColumn DataField="CurrencyValue"
HeaderText="Price"
DataFormatString="{0:c}">
<ItemStyle HorizontalAlign="Right">
</ItemStyle>
</asp:BoundColumn>
<asp:TemplateColumn HeaderText="Select Item">
<ItemTemplate>
<asp:CheckBox id="SelectCheckBox"
Text="Add to Cart"
Checked='<%# DataBinder.Eval(Container.DataItem, "BooleanValue") %>'
runat="server"/>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>
<br /><br />
<asp:Button id="SubmitButton"
Text="Submit"
OnClick = "Button_Click"
runat="server"/>
</form>
</body>
</html>
Commenti
Utilizzare la HeaderText proprietà per specificare o determinare il testo visualizzato nella sezione di intestazione della colonna. Se si desidera visualizzare un'immagine invece di testo nella sezione di intestazione della colonna, impostare la proprietà anziché questa HeaderImageUrl proprietà.
Attenzione
Il testo non è codificato in formato HTML prima che venga visualizzato nella sezione intestazione della colonna. In questo modo è possibile incorporare lo script all'interno di tag HTML nel testo. Se questa proprietà viene impostata in modo dinamico usando l'input dell'utente, assicurarsi di convalidare il valore per ridurre le vulnerabilità di sicurezza.
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