GridView.SortExpression Egenskap
Definition
Viktigt
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Hämtar sorteringsuttrycket som är associerat med kolumnen eller kolumnerna som sorteras.
public:
virtual property System::String ^ SortExpression { System::String ^ get(); };[System.ComponentModel.Browsable(false)]
public virtual string SortExpression { get; }[<System.ComponentModel.Browsable(false)>]
member this.SortExpression : stringPublic Overridable ReadOnly Property SortExpression As StringEgenskapsvärde
Sorteringsuttrycket som är associerat med kolumnen eller kolumnerna som sorteras.
- Attribut
Exempel
I följande exempel visas hur du använder SortExpression egenskapen för att fastställa namnet på kolumnen som sorteras.
<%@ Page language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
void CustomersGridView_RowCreated(Object sender, GridViewRowEventArgs e)
{
// Use the RowType property to determine whether the
// row being created is the header row.
if (e.Row.RowType == DataControlRowType.Header)
{
// Call the GetSortColumnIndex helper method to determine
// the index of the column being sorted.
int sortColumnIndex = GetSortColumnIndex();
if (sortColumnIndex != -1)
{
// Call the AddSortImage helper method to add
// a sort direction image to the appropriate
// column header.
AddSortImage(sortColumnIndex, e.Row);
}
}
}
// This is a helper method used to determine the index of the
// column being sorted. If no column is being sorted, -1 is returned.
int GetSortColumnIndex()
{
// Iterate through the Columns collection to determine the index
// of the column being sorted.
foreach (DataControlField field in CustomersGridView.Columns)
{
if (field.SortExpression == CustomersGridView.SortExpression)
{
return CustomersGridView.Columns.IndexOf(field);
}
}
return -1;
}
// This is a helper method used to add a sort direction
// image to the header of the column being sorted.
void AddSortImage(int columnIndex, GridViewRow headerRow)
{
// Create the sorting image based on the sort direction.
Image sortImage = new Image();
if (CustomersGridView.SortDirection == SortDirection.Ascending)
{
sortImage.ImageUrl = "~/Images/Ascending.jpg";
sortImage.AlternateText = "Ascending Order";
}
else
{
sortImage.ImageUrl = "~/Images/Descending.jpg";
sortImage.AlternateText = "Descending Order";
}
// Add the image to the appropriate header cell.
headerRow.Cells[columnIndex].Controls.Add(sortImage);
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView AllowSorting Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView AllowSorting Example</h3>
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSource"
autogeneratecolumns="false"
emptydatatext="No data available."
allowsorting="true"
onrowcreated="CustomersGridView_RowCreated"
runat="server">
<columns>
<asp:boundfield datafield="CustomerID"
headertext="Customer ID"
headerstyle-wrap="false"
sortexpression="CustomerID"/>
<asp:boundfield datafield="CompanyName"
headertext="CompanyName"
headerstyle-wrap="false"
sortexpression="CompanyName"/>
<asp:boundfield datafield="Address"
headertext="Address"
headerstyle-wrap="false"
sortexpression="Address"/>
<asp:boundfield datafield="City"
headertext="City"
headerstyle-wrap="false"
sortexpression="City"/>
<asp:boundfield datafield="PostalCode"
headertext="Postal Code"
headerstyle-wrap="false"
sortexpression="PostalCode" />
<asp:boundfield datafield="Country"
headertext="Country"
headerstyle-wrap="false"
sortexpression="Country"/>
</columns>
</asp:gridview>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="CustomersSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
<%@ Page language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Sub CustomersGridView_RowCreated(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
' Use the RowType property to determine whether the
' row being created is the header row.
If e.Row.RowType = DataControlRowType.Header Then
' Call the GetSortColumnIndex helper method to determine
' the index of the column being sorted.
Dim sortColumnIndex As Integer = GetSortColumnIndex()
If sortColumnIndex <> -1 Then
' Call the AddSortImage helper method to add
' a sort direction image to the appropriate
' column header.
AddSortImage(sortColumnIndex, e.Row)
End If
End If
End Sub
' This is a helper method used to determine the index of the
' column being sorted. If no column is being sorted, -1 is returned.
Function GetSortColumnIndex() As Integer
' Iterate through the Columns collection to determine the index
' of the column being sorted.
Dim field As DataControlField
For Each field In CustomersGridView.Columns
If field.SortExpression = CustomersGridView.SortExpression Then
Return CustomersGridView.Columns.IndexOf(field)
End If
Next
Return -1
End Function
' This is a helper method used to add a sort direction
' image to the header of the column being sorted.
Sub AddSortImage(ByVal columnIndex As Integer, ByVal row As GridViewRow)
' Create the sorting image based on the sort direction.
Dim sortImage As New Image()
If CustomersGridView.SortDirection = SortDirection.Ascending Then
sortImage.ImageUrl = "~/Images/Ascending.jpg"
sortImage.AlternateText = "Ascending Order"
Else
sortImage.ImageUrl = "~/Images/Descending.jpg"
sortImage.AlternateText = "Descending Order"
End If
' Add the image to the appropriate header cell.
row.Cells(columnIndex).Controls.Add(sortImage)
End Sub
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>GridView AllowSorting Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>GridView AllowSorting Example</h3>
<asp:gridview id="CustomersGridView"
datasourceid="CustomersSource"
autogeneratecolumns="false"
emptydatatext="No data available."
allowsorting="true"
onrowcreated="CustomersGridView_RowCreated"
runat="server">
<columns>
<asp:boundfield datafield="CustomerID"
headertext="Customer ID"
headerstyle-wrap="false"
sortexpression="CustomerID"/>
<asp:boundfield datafield="CompanyName"
headertext="CompanyName"
headerstyle-wrap="false"
sortexpression="CompanyName"/>
<asp:boundfield datafield="Address"
headertext="Address"
headerstyle-wrap="false"
sortexpression="Address"/>
<asp:boundfield datafield="City"
headertext="City"
headerstyle-wrap="false"
sortexpression="City"/>
<asp:boundfield datafield="PostalCode"
headertext="Postal Code"
headerstyle-wrap="false"
sortexpression="PostalCode" />
<asp:boundfield datafield="Country"
headertext="Country"
headerstyle-wrap="false"
sortexpression="Country"/>
</columns>
</asp:gridview>
<!-- This example uses Microsoft SQL Server and connects -->
<!-- to the Northwind sample database. Use an ASP.NET -->
<!-- expression to retrieve the connection string value -->
<!-- from the Web.config file. -->
<asp:sqldatasource id="CustomersSource"
selectcommand="Select [CustomerID], [CompanyName], [Address], [City], [PostalCode], [Country] From [Customers]"
connectionstring="<%$ ConnectionStrings:NorthWindConnectionString%>"
runat="server"/>
</form>
</body>
</html>
Kommentarer
Använd egenskapen SortExpression för att fastställa sorteringsuttrycket som är associerat med kolumnen eller kolumnerna som sorteras.
Note
Kontrollen GridView har en inbyggd sorteringsfunktion som automatiskt anger den här egenskapen. Den här egenskapen används vanligtvis endast när du programmatiskt behöver fastställa vilken kolumn eller vilka kolumner som sorteras eller när du lägger till din egen anpassade sorteringsfunktion i en GridView kontroll.
När flera kolumner sorteras innehåller den här egenskapen en kommaavgränsad lista över de fält som ska sorteras efter.
