DataGrid.BackImageUrl Vlastnost
Definice
Důležité
Některé informace platí pro předběžně vydaný produkt, který se může zásadně změnit, než ho výrobce nebo autor vydá. Microsoft neposkytuje žádné záruky, výslovné ani předpokládané, týkající se zde uváděných informací.
Získá nebo nastaví adresu URL obrázku na pozadí DataGrid ovládacího prvku.
public:
virtual property System::String ^ BackImageUrl { System::String ^ get(); void set(System::String ^ value); };[System.ComponentModel.Bindable(true)]
public virtual string BackImageUrl { get; set; }public virtual string BackImageUrl { get; set; }[<System.ComponentModel.Bindable(true)>]
member this.BackImageUrl : string with get, setmember this.BackImageUrl : string with get, setPublic Overridable Property BackImageUrl As StringHodnota vlastnosti
Adresa URL obrázku, který se má zobrazit na pozadí DataGrid ovládacího prvku. Výchozí hodnota je Empty.
- Atributy
Příklady
Následující příklad kódu ukazuje, jak pomocí BackImageUrl vlastnosti určit obrázek pozadí pro DataGrid ovládací prvek.
<%@ 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">
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 (!IsPostBack)
{
// Need to load this data only once.
ItemsGrid.DataSource= CreateDataSource();
ItemsGrid.DataBind();
}
}
</script>
<head runat="server">
<title>DataGrid BackImageUrl Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGrid BackImageUrl Example</h3>
<b>Product List</b>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
AutoGenerateColumns="true"
BackImageUrl="Images\image1.jpg"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
</asp:DataGrid>
</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">
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 Not IsPostBack Then
' Need to load this data only once.
ItemsGrid.DataSource = CreateDataSource()
ItemsGrid.DataBind()
End If
End Sub 'Page_Load
</script>
<head runat="server">
<title>DataGrid BackImageUrl Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGrid BackImageUrl Example</h3>
<b>Product List</b>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
AutoGenerateColumns="true"
BackImageUrl="Images\image1.jpg"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
</asp:DataGrid>
</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)));
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();
}
// This version of UpdateSource updates the data source and
// calculates the subtotal.
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;
}
// This version of UpdateSource updates the data source only.
DataTable UpdateSource()
{
// 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;
}
}
// Save the data source.
Session["Source"] = dt;
return dt;
}
void Selection_Change(Object sender, EventArgs e)
{
// Set the image for the header section of the first column in
// the DataGrid control.
ItemsGrid.BackImageUrl = List.SelectedItem.Value;
// Create a DataView and bind it to the DataGrid control. This
// will refresh the DataGrid control with the updated header image.
DataView dv = new DataView(UpdateSource());
ItemsGrid.DataSource = dv;
ItemsGrid.DataBind();
}
</script>
<head runat="server">
<title>DataGrid BackImageUrl Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGrid BackImageUrl Example</h3>
Select a background image for the DataGrid control.
<br /><br />
<b>Product List</b>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
ShowFooter="True"
AutoGenerateColumns="False"
BackImageUrl="image1.jpg"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
<FooterStyle BackColor="#00aaaa">
</FooterStyle>
<Columns>
<asp:BoundColumn DataField="IntegerValue"/>
<asp:BoundColumn DataField="StringValue"/>
<asp:BoundColumn DataField="CurrencyValue"
DataFormatString="{0:c}">
<ItemStyle HorizontalAlign="Right">
</ItemStyle>
</asp:BoundColumn>
<asp:TemplateColumn>
<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"/>
<hr />
Background image: <br />
<asp:DropDownList id="List"
AutoPostBack="True"
OnSelectedIndexChanged="Selection_Change"
runat="server">
<asp:ListItem Selected="True" Value="image1.jpg"> Image 1 </asp:ListItem>
<asp:ListItem Value="image2.jpg"> Image 2 </asp:ListItem>
<asp:ListItem Value="image3.jpg"> Image 3 </asp:ListItem>
<asp:ListItem Value="image4.jpg"> Image 4 </asp:ListItem>
</asp:DropDownList>
</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
' This version of UpdateSource updates the data source and
' calculates the subtotal.
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
' This version of UpdateSource updates the data source only.
Function UpdateSource() 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
End If
Next
' Save the data source.
Session("Source") = dt
Return dt
End Function
Sub Selection_Change(sender As Object, e As EventArgs)
' Set the image for the header section of the first column in
' the DataGrid control.
ItemsGrid.BackImageUrl = List.SelectedItem.Value
' Create a DataView and bind it to the DataGrid control. This
' will refresh the DataGrid control with the updated header image.
Dim dv As DataView = New DataView(UpdateSource())
ItemsGrid.DataSource = dv
ItemsGrid.DataBind()
End Sub
</script>
<head runat="server">
<title>DataGrid BackImageUrl Example</title>
</head>
<body>
<form id="form1" runat="server">
<h3>DataGrid BackImageUrl Example</h3>
Select a background image for the DataGrid control.
<br /><br />
<b>Product List</b>
<asp:DataGrid id="ItemsGrid"
BorderColor="black"
BorderWidth="1"
CellPadding="3"
ShowFooter="True"
AutoGenerateColumns="False"
BackImageUrl="image1.jpg"
runat="server">
<HeaderStyle BackColor="#00aaaa">
</HeaderStyle>
<FooterStyle BackColor="#00aaaa">
</FooterStyle>
<Columns>
<asp:BoundColumn DataField="IntegerValue"/>
<asp:BoundColumn DataField="StringValue"/>
<asp:BoundColumn DataField="CurrencyValue"
DataFormatString="{0:c}">
<ItemStyle HorizontalAlign="Right">
</ItemStyle>
</asp:BoundColumn>
<asp:TemplateColumn>
<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"/>
<hr />
Background image: <br />
<asp:DropDownList id="List"
AutoPostBack="True"
OnSelectedIndexChanged="Selection_Change"
runat="server">
<asp:ListItem Selected="True" Value="image1.jpg"> Image 1 </asp:ListItem>
<asp:ListItem Value="image2.jpg"> Image 2 </asp:ListItem>
<asp:ListItem Value="image3.jpg"> Image 3 </asp:ListItem>
<asp:ListItem Value="image4.jpg"> Image 4 </asp:ListItem>
</asp:DropDownList>
</form>
</body>
</html>
Poznámky
BackImageUrl Pomocí vlastnosti určete obrázek, který se má zobrazit na pozadí DataGrid ovládacího prvku.
Poznámka
Pokud je zadaný obrázek menší než DataGrid ovládací prvek, zobrazí se dlaždice, která vyplní pozadí ovládacího prvku.
Platí pro
Viz také
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