BoundColumn.DataFormatString 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 la stringa in cui è specificato il formato di visualizzazione per gli elementi della colonna.
public:
virtual property System::String ^ DataFormatString { System::String ^ get(); void set(System::String ^ value); };public virtual string DataFormatString { get; set; }member this.DataFormatString : string with get, setPublic Overridable Property DataFormatString As StringValore della proprietà
Stringa di formattazione in cui è specificato il formato di visualizzazione per gli elementi della colonna. Il valore predefinito è Empty.
Esempio
Nell'esempio seguente viene illustrato come utilizzare la DataFormatString proprietà per specificare vari formati per le colonne nel DataGrid controllo . La Qty colonna viene formattata come numero intero, la Price colonna viene formattata come valuta, la Weight colonna viene formattata come numero decimale e la Expires colonna viene formattata come stringa di data e ora breve.
<%@ Page language="c#" AutoEventWireup="true" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Globalization" %>
<!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" >
<head runat="server">
<title>BoundColumn Example</title>
</head>
<script runat="server">
// The Cart and CartView objects temporarily store the data source
// for the DataGrid control while the page is being processed.
DataTable Cart;
DataView CartView;
void Page_Load(Object sender, EventArgs e)
{
// With a database, use a select query to retrieve the data.
// Because the data source in this example is an in-memory
// DataTable, retrieve the data from session state if it exists;
// otherwise, create the data source.
GetSource();
// The DataGrid control maintains state between posts to the
// server; therefore it only needs to be bound to a data source
// the first time the page is loaded or when the data source
// is updated.
if (!IsPostBack)
{
BindGrid();
}
}
void ItemsGrid_Edit(Object sender, DataGridCommandEventArgs e)
{
// Set the EditItemIndex property to the index of the item
// clicked in the DataGrid control to enable editing for that
// item. Be sure to rebind the DateGrid to the data source
// to refresh the control.
ItemsGrid.EditItemIndex = e.Item.ItemIndex;
BindGrid();
}
void ItemsGrid_Cancel(Object sender, DataGridCommandEventArgs e)
{
// Set the EditItemIndex property to -1 to exit editing mode.
// Be sure to rebind the DateGrid to the data source to
// refresh the control.
ItemsGrid.EditItemIndex = -1;
BindGrid();
}
void ItemsGrid_Update(Object sender, DataGridCommandEventArgs e)
{
// Retrieve the updated values.
// For bound columns, the edited value is stored in a TextBox.
// The TextBox is the 0th control in a cell's Controls collection.
// Each cell in the Cells collection of a DataGrid item represents
// a column in the DataGrid control.
DataGridItem updateItem = e.Item;
TextBox qtyText = (TextBox)updateItem.Cells[2].Controls[0];
TextBox priceText = (TextBox)updateItem.Cells[3].Controls[0];
try {
// Try to parse the updated values from the input text.
Int32 newQty;
Decimal newPrice;
newQty = Int32.Parse(qtyText.Text, NumberStyles.Number);
newPrice = Decimal.Parse(priceText.Text, NumberStyles.Currency);
// Get the item cell value - "Item 1", "Item 2", etc.
// For read-only columns, the value is stored in the cell text.
String item = updateItem.Cells[1].Text;
// With a database, use an update command to update the data.
// Because the data source in this example is an in-memory
// DataTable, delete the old row and replace it with a new one.
// Filter on the updated item, remove it,
// then clear the row filter.
CartView.RowFilter = "Item='" + item + "'";
if (CartView.Count > 0)
{
CartView.Delete(0);
}
CartView.RowFilter = "";
// Add the updated entry for the item.
DataRow dr = Cart.NewRow();
dr["Item"] = item;
dr["Qty"] = newQty;
dr["Price"] = newPrice;
dr["Weight"] = updateItem.Cells[4].Text;
dr["Expires"] = updateItem.Cells[5].Text;
Cart.Rows.Add(dr);
}
catch (System.FormatException)
{
// If parsing the price or quantity caused an
// exception, then leave edit mode without
// changing any cell values.
}
// Set the EditItemIndex property to -1 to exit editing mode.
// Be sure to rebind the DataGrid to the data source to refresh
// the control.
ItemsGrid.EditItemIndex = -1;
BindGrid();
}
void BindGrid()
{
// Set the data source and bind to the Data Grid control.
ItemsGrid.DataSource = CartView;
ItemsGrid.DataBind();
}
void GetSource()
{
// For this example, the data source is a DataTable that is
// stored in session state.
// If the data source does not exist, create it; otherwise,
// load the data.
if (Session["ShoppingCart"] == null)
{
Cart = new DataTable();
InitSource();
}
else
{
// Retrieve the sample data from session state.
Cart = (DataTable)Session["ShoppingCart"];
}
// Create a DataView and specify the field to sort by.
CartView = new DataView(Cart);
CartView.Sort="Item";
return;
}
void InitSource()
{
// Create the sample data.
// Define the columns of the table.
Cart.Columns.Add(new DataColumn("Qty", typeof(Int32)));
Cart.Columns.Add(new DataColumn("Item", typeof(String)));
Cart.Columns.Add(new DataColumn("Price", typeof(Decimal)));
Cart.Columns.Add(new DataColumn("Weight", typeof(Decimal)));
Cart.Columns.Add(new DataColumn("Expires", typeof(DateTime)));
// Store the table in session state to persist its values
// between posts to the server.
Session["ShoppingCart"] = Cart;
// Populate the DataTable with sample data.
DataRow dr;
for (int i = 1; i <= 4; i++)
{
dr = Cart.NewRow();
dr["Qty"] = i % 2 + 1;
dr["Item"] = "Item " + i.ToString();
dr["Price"] = (0.50 * (i + 1));
dr["Weight"] = 5.0;
dr["Expires"] = DateTime.Now + TimeSpan.FromDays(7);
Cart.Rows.Add(dr);
}
}
</script>
<body>
<form runat="server" id="form1">
<h3>BoundColumn DataFormatString Example</h3>
<asp:DataGrid id="ItemsGrid"
BorderColor="black" BorderWidth="1" CellPadding="3"
OnEditCommand="ItemsGrid_Edit" OnCancelCommand="ItemsGrid_Cancel"
OnUpdateCommand="ItemsGrid_Update" AutoGenerateColumns="false"
runat="server" >
<HeaderStyle backcolor="#aaaadd"></HeaderStyle>
<Columns>
<asp:EditCommandColumn EditText="Edit" CancelText="Cancel"
UpdateText="Update" HeaderText="Edit Command Column">
<ItemStyle Wrap="False"></ItemStyle>
<HeaderStyle wrap="false"></HeaderStyle>
</asp:EditCommandColumn>
<asp:BoundColumn HeaderText="Item" DataField="Item"
ReadOnly="True" />
<asp:BoundColumn HeaderText="Quantity" DataField="Qty"
DataFormatString="{0:N0}"/>
<asp:BoundColumn HeaderText="Price" DataField="Price"
DataFormatString="{0:c}" />
<asp:BoundColumn HeaderText="Weight" DataField="Weight"
ReadOnly="True" DataFormatString="{0:F3}" />
<asp:BoundColumn HeaderText="Expires" DataField="Expires"
ReadOnly="True" DataFormatString="{0:g}" />
</Columns>
</asp:DataGrid>
</form>
</body>
</html>
<%@ Page language="VB" AutoEventWireup="true" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Globalization" %>
<!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" >
<head runat="server">
<title>BoundColumn Example</title>
</head>
<script runat="server">
' The Cart and CartView objects temporarily store the data source
' for the DataGrid control while the page is being processed.
Dim Cart As DataTable
Dim CartView As DataView
Sub Page_Load(sender as Object, e As EventArgs)
' With a database, use a select query to retrieve the data.
' Because the data source in this example is an in-memory
' DataTable, retrieve the data from session state if it exists;
' otherwise, create the data source.
GetSource()
' The DataGrid control maintains state between posts to the
' server; therefore it only needs to be bound to a data source
' the first time the page is loaded or when the data source
' is updated.
If Not IsPostBack Then
BindGrid()
End If
End Sub
Sub ItemsGrid_Edit(sender As Object, e As DataGridCommandEventArgs)
' Set the EditItemIndex property to the index of the item
' clicked in the DataGrid control to enable editing for that
' item. Be sure to rebind the DateGrid to the data source
' to refresh the control.
ItemsGrid.EditItemIndex = e.Item.ItemIndex
BindGrid()
End Sub
Sub ItemsGrid_Cancel(sender As Object, e As DataGridCommandEventArgs)
' Set the EditItemIndex property to -1 to exit editing mode.
' Be sure to rebind the DateGrid to the data source to
' refresh the control.
ItemsGrid.EditItemIndex = -1
BindGrid()
End Sub
Sub ItemsGrid_Update(sender As Object, e As DataGridCommandEventArgs)
' Retrieve the updated values.
' For bound columns, the edited value is stored in a TextBox.
' The TextBox is the 0th control in a cell's Controls collection.
' Each cell in the Cells collection of a DataGrid item represents
' a column in the DataGrid control.
Dim updateItem As DataGridItem
updateItem = e.Item
Dim qtyText As TextBox = CType(e.Item.Cells(2).Controls(0), TextBox)
Dim priceText As TextBox = CType(e.Item.Cells(3).Controls(0), TextBox)
Try
' Try to parse the updated values from the input text.
Dim newQty As Int32
Dim newPrice As Decimal
newQty = Int32.Parse(qtyText.Text, NumberStyles.Number)
newPrice = Decimal.Parse(priceText.Text, NumberStyles.Currency)
' Get the item cell value - "Item 1", "Item 2", etc.
' For read-only columns, the value is stored in the cell text.
Dim item As String = updateItem.Cells(1).Text
' With a database, use an update command to update the data. Because
' the data source in this example is an in-memory DataTable, delete
' the old row and replace it with a new one.
' Remove the old entry and clear the row filter.
CartView.RowFilter = "Item='" & item & "'"
If CartView.Count > 0 Then
CartView.Delete(0)
End If
CartView.RowFilter = ""
' Add the new entry.
Dim dr As DataRow
dr = Cart.NewRow()
dr("Item") = item
dr("Qty") = newQty
dr("Price") = newPrice
dr("Weight") = updateItem.Cells(4).Text
dr("Expires") = updateItem.Cells(5).Text
Cart.Rows.Add(dr)
Catch ex As System.FormatException
' If parsing the price or quantity caused an
' exception, then leave edit mode without
' changing any cell values.
End Try
' Set the EditItemIndex property to -1 to exit editing mode.
' Be sure to rebind the DateGrid to the data source to refresh
' the control.
ItemsGrid.EditItemIndex = -1
BindGrid()
End Sub
Sub BindGrid()
' Set the data source and bind to the Data Grid control.
ItemsGrid.DataSource = CartView
ItemsGrid.DataBind()
End Sub
Sub GetSource()
' For this example, the data source will be a DataTable that is
' stored in session state.
' If the data source does not exist, create it; otherwise,
' load the data.
If Session("ShoppingCart") Is Nothing Then
Cart = New DataTable
InitSource()
Else
' Retrieve the sample data from session state.
Cart = CType(Session("ShoppingCart"), DataTable)
End If
' Create a DataView and specify the field to sort by.
CartView = New DataView(Cart)
CartView.Sort="Item"
Return
End Sub
Sub InitSource()
' Create the sample data.
' Define the columns of the table.
Cart.Columns.Add(New DataColumn("Qty", GetType(System.Int32)))
Cart.Columns.Add(New DataColumn("Item", GetType(System.String)))
Cart.Columns.Add(New DataColumn("Price", GetType(System.Decimal)))
Cart.Columns.Add(New DataColumn("Weight", GetType(System.Decimal)))
Cart.Columns.Add(New DataColumn("Expires", GetType(System.DateTime)))
' Store the table in session state to persist its values
' between posts to the server.
Session("ShoppingCart") = Cart
' Populate the DataTable with sample data.
' The generated table row data look like this:
Dim dr As DataRow
Dim i As Integer
For i = 1 to 4
dr = Cart.NewRow()
dr("Qty") = i Mod 2 + 1
dr("Item") = "Item " + i.ToString()
dr("Price") = (0.5 * (i + 1))
dr("Weight") = 5.0
dr("Expires") = DateTime.Now + TimeSpan.FromDays(7)
Cart.Rows.Add(dr)
Next
End Sub
</script>
<body>
<form runat="server" id="form1">
<h3>BoundColumn DataFormatString Example</h3>
<asp:DataGrid id="ItemsGrid"
BorderColor="black" BorderWidth="1" CellPadding="3"
OnEditCommand="ItemsGrid_Edit" OnCancelCommand="ItemsGrid_Cancel"
OnUpdateCommand="ItemsGrid_Update" AutoGenerateColumns="false"
runat="server" >
<HeaderStyle backcolor="#aaaadd"></HeaderStyle>
<Columns>
<asp:EditCommandColumn EditText="Edit" CancelText="Cancel"
UpdateText="Update" HeaderText="Edit Command Column">
<ItemStyle Wrap="False"></ItemStyle>
<HeaderStyle wrap="false"></HeaderStyle>
</asp:EditCommandColumn>
<asp:BoundColumn HeaderText="Item" DataField="Item"
ReadOnly="True" />
<asp:BoundColumn HeaderText="Quantity" DataField="Qty"
DataFormatString="{0:N0}"/>
<asp:BoundColumn HeaderText="Price" DataField="Price"
DataFormatString="{0:c}" />
<asp:BoundColumn HeaderText="Weight" DataField="Weight"
ReadOnly="True" DataFormatString="{0:F3}" />
<asp:BoundColumn HeaderText="Expires" DataField="Expires"
ReadOnly="True" DataFormatString="{0:g}" />
</Columns>
</asp:DataGrid>
</form>
</body>
</html>
Commenti
Utilizzare la DataFormatString proprietà per fornire un formato personalizzato per gli elementi nella colonna.
La stringa di formato dati è costituita da due parti, separate da due punti, nel formato { A : Bxx }. Ad esempio, la stringa {0:F2} di formattazione visualizza un numero a virgola fissa con due posizioni decimali.
Nota
L'intera stringa deve essere racchiusa tra parentesi graffe per indicare che si tratta di una stringa di formato e non di una stringa letterale. Qualsiasi testo all'esterno delle parentesi graffe viene visualizzato come testo letterale.
Il valore prima dei due punti (A nell'esempio generale) specifica l'indice dei parametri in un elenco in base zero di parametri.
Nota
Questo valore può essere impostato solo su 0 perché in ogni cella è presente un solo valore.
Il carattere dopo i due punti (B nell'esempio generale) specifica il formato in cui visualizzare il valore. Nella tabella seguente sono elencati i formati comuni.
| Formato carattere | Descrizione |
|---|---|
C |
Visualizza i valori numerici in formato valuta. |
D |
Visualizza i valori numerici in formato decimale. |
E |
Visualizza i valori numerici in formato scientifico (esponenziale). |
F |
Visualizza i valori numerici in formato fisso. |
G |
Visualizza i valori numerici in formato generale. |
N |
Visualizza i valori numerici in formato numerico. |
X |
Visualizza i valori numerici in formato esadecimale. |
Nota
Il carattere di formato non fa distinzione tra maiuscole e minuscole, ad eccezione Xdi , che visualizza i caratteri esadecimali nel caso specificato.
Il valore dopo il carattere di formato (xx nell'esempio generale) specifica il numero di cifre significative o cifre decimali da visualizzare.
Per altre informazioni sulla formattazione delle stringhe, vedere Formatting Types (Formattazione dei tipi).
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