ASP.NET Tutorial/ASP.net Controls/Image — различия между версиями

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Текущая версия на 12:00, 26 мая 2010

Image alignment

<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="Default_aspx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Image Control</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <h1>Image Control</h1>
     <asp:Image ID="img1" runat="server" AlternateText="Dan" ImageUrl="http://www.nfex.ru/style/logo.png" />
    
      <hr />
     <asp:Button runat="server" Text="Sample Button" />
     
     <asp:Image ID="img2" runat="server" AlternateText="Dan" ImageUrl="http://www.nfex.ru/style/logo.png" />
     
     <hr />
     
     <asp:DropDownList ID="ddl" runat="server" AutoPostBack="True">
         <asp:ListItem text="NotSet" />
         <asp:ListItem text="AbsBottom" />
         <asp:ListItem text="AbsMiddle" />
         <asp:ListItem text="Top" />
         <asp:ListItem text="Bottom" />
         <asp:ListItem text="BaseLine" />
         <asp:ListItem text="TextTop" />
         <asp:ListItem text="Left" />
         <asp:ListItem text="Right" />
     </asp:DropDownList>
    </div>
    </form>
</body>
</html>
File: Default.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class Default_aspx : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {
     switch (ddl.SelectedIndex)
     {
       case 0:
         img1.ImageAlign = ImageAlign.NotSet;
         img2.ImageAlign = ImageAlign.NotSet;
         break;
       case 1:
         img1.ImageAlign = ImageAlign.AbsBottom;
         img2.ImageAlign = ImageAlign.AbsBottom;
         break;
       case 2:
         img1.ImageAlign = ImageAlign.AbsMiddle;
         img2.ImageAlign = ImageAlign.AbsMiddle;
         break;
       case 3:
         img1.ImageAlign = ImageAlign.Top;
         img2.ImageAlign = ImageAlign.Top;
         break;
       case 4:
         img1.ImageAlign = ImageAlign.Bottom;
         img2.ImageAlign = ImageAlign.Bottom;
         break;
       case 5:
         img1.ImageAlign = ImageAlign.Baseline;
         img2.ImageAlign = ImageAlign.Baseline;
         break;
       case 6:
         img1.ImageAlign = ImageAlign.Middle;
         img2.ImageAlign = ImageAlign.Middle;
         break;
       case 7:
         img1.ImageAlign = ImageAlign.TextTop;
         img2.ImageAlign = ImageAlign.TextTop;
         break;
       case 8:
         img1.ImageAlign = ImageAlign.Left;
         img2.ImageAlign = ImageAlign.Left;
         break;
       case 9:
         img1.ImageAlign = ImageAlign.Right;
         img2.ImageAlign = ImageAlign.Right;
         break;
       default:
         img1.ImageAlign = ImageAlign.NotSet;
         img2.ImageAlign = ImageAlign.NotSet;
         break;
     }
    }
}


Important properties of Image control

AlternateText:              alternate text for the image required for accessibility.
DescriptionUrl:             a link to a page that contains a detailed description of the image (required to make a complex image accessible).
GenerateEmptyAlternateText: set the AlternateText property to an empty string.
ImageAlign:                 align the image relative to other HTML elements in the page. Possible values are AbsBottom, AbsMiddle, Baseline, Bottom, Left, Middle, NotSet, Right, TextTop, and Top.
ImageUrl:                   specify the URL to the image.

<%@ 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 Page_Load()
    {
        Random rnd = new Random();
        switch (rnd.Next(3))
        {
            case 0:
                imgRandom.ImageUrl = "Picture1.gif";
                imgRandom.AlternateText = "Picture 1";
                break;
            case 1:
                imgRandom.ImageUrl = "Picture2.gif";
                imgRandom.AlternateText = "Picture 2";
                break;
            case 2:
                imgRandom.ImageUrl = "Picture3.gif";
                imgRandom.AlternateText = "Picture 3";
                break;
        }
    }
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Show Image</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <asp:Image
        id="imgRandom"
        Runat="server" />
    </div>
    </form>
</body>
</html>


Load Image to asp:Image

<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %>
<!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>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <div>
            <asp:Label ID="Label1" runat="server" Height="32px" Text="Image to display" Width="176px"></asp:Label>
            <asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" Width="112px">
                <asp:ListItem>A</asp:ListItem>
                <asp:ListItem>B</asp:ListItem>
            </asp:DropDownList>
            <div>
                <asp:Button ID="Button1" runat="server" Text="Select Image" /></div>
        </div>
        <div>
            <asp:Image ID="Image1" 
                       runat="server" 
                       AlternateText="Image" 
                       Height="128px" 
                       ToolTip="Image"
                       Width="208px" /></div>
    
    </div>
    </form>
</body>
</html>

File: Default.aspx.vb

Partial Class _Default
    Inherits System.Web.UI.Page
    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Select Case DropDownList1.SelectedIndex
            Case 0
                Image1.ImageUrl = "http://www.nfex.ru/style/logo.png"
            Case 1
                Image1.ImageUrl = "http://www.nfex.ru/style/logo.png"
        End Select
    End Sub
End Class


Set ImageUrl and AlternateText for asp:Image (VB.net)

<%@ 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 Page_Load()
        Dim rnd As New Random()
        Select Case rnd.Next(3)
            Case 0
                imgRandom.ImageUrl = "Picture1.gif"
                imgRandom.AlternateText = "Picture 1"
            Case 1
                imgRandom.ImageUrl = "Picture2.gif"
                imgRandom.AlternateText = "Picture 2"
            Case 2
                imgRandom.ImageUrl = "Picture3.gif"
                imgRandom.AlternateText = "Picture 3"
        End Select
    End Sub
    
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Show Image</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <asp:Image
        id="imgRandom"
        Runat="server" />
    
    </div>
    </form>
</body>
</html>
Источник — «http://nfex.ru/index.php?title=ASP.NET_Tutorial/ASP.net_Controls/Image&oldid=3363»