C# 要基于SQL值显示图像吗？
希望这里有人能帮我！。在gridview中，我有字段附件，值取自SQL。我试图评估附件字段，如果它包含文本，则显示附件Img，否则-nothing或NoAttch.jpg 我尝试创建ASP图像并使用代码隐藏来评估img，但没有显示图像。 任何帮助，让我发疯C# 要基于SQL值显示图像吗？,c#,asp.net,.net,sql,C#,Asp.net,.net,Sql,希望这里有人能帮我！。在gridview中，我有字段附件，值取自SQL。我试图评估附件字段，如果它包含文本，则显示附件Img，否则-nothing或NoAttch.jpg 我尝试创建ASP图像并使用代码隐藏来评估img，但没有显示图像。 任何帮助，让我发疯 <asp:GridView ID="GridView2" runat="server" AutoGenerateColumns="False" DataSourceID="BookingsSQL" ShowHeader="False
<asp:GridView ID="GridView2" runat="server" AutoGenerateColumns="False" DataSourceID="BookingsSQL"
ShowHeader="False" Width="80%" BackColor="Azure" GridLines="Horizontal"
DataKeyNames="ID" AllowSorting="True" HorizontalAlign="Center" AutoGenerateDeleteButton="false">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<table id="Table1" runat="server" visible="<%# Container.DataItemIndex == 0 %>">
<tr>
<th width="20%">
<asp:LinkButton ID="LinkButton1" runat="server" CommandName="Sort" CommandArgument="programme_name" >
Programme Name
</asp:LinkButton>
</th>
<th width="10%">
<asp:LinkButton ID="LinkButton2" runat="server" CommandName="Sort" CommandArgument="Start">
Start
</asp:LinkButton>
</th>
<th width="10%">
<asp:LinkButton ID="LinkButton3" runat="server" CommandName="Sort" CommandArgument="Finish">
Finish
</asp:LinkButton>
</th>
<th width="20%">
<asp:LinkButton ID="LinkButton4" runat="server" CommandName="Sort" CommandArgument="Source">
Source
</asp:LinkButton>
</th>
<th width="20%">
<asp:LinkButton ID="LinkButton5" runat="server" CommandName="Sort" CommandArgument="Destination">
Destination
</asp:LinkButton>
</th>
<th width="40%">
<asp:LinkButton ID="LinkButton6" runat="server" CommandName="Sort" CommandArgument="BComment">
Comment
</asp:LinkButton>
</th>
<th width="10%">
<asp:LinkButton ID="LinkButton15" runat="server" CommandName="Sort" CommandArgument="Attachment">
Attachment
</asp:LinkButton>
</th>
</tr>
</table>
<asp:Panel runat="server" ID="ItemContainer">
<table width="80%">
<tr>
<td width="10%">
<%# Eval("programme_name") %>
</td>
<td width="10%">
<%# Eval("Start") %>
</td>
<td width="10%">
<%# Eval("Finish") %>
</td>
<td width="20%">
<%# Eval("Source") %>
</td>
<td width="20%">
<%# Eval("Destination") %>
</td>
<td width="40%">
<%# Eval("BComment") %>
</td>
<td width="10%">
<%# Eval("Attachment") %>
</td>
</tr>
</table>
</asp:Panel>
<asp:Panel CssClass="popupMenu" ID="PopupMenu" runat="server">
<asp:LinkButton ID="LinkButton7" runat="server" CommandName="Edit" Text="Edit" />
<br />
<asp:LinkButton ID="LinkButton8" runat="server" CommandName="Insert" CausesValidation="true"
Text="Insert" />
<br />
<asp:LinkButton ID="LinkButton16" runat="server" CommandName="Delete" CausesValidation="true"
Text="Delete" />
</asp:Panel>
<ajaxToolkit:HoverMenuExtender runat="server" TargetControlID="ItemContainer" PopupControlID="popupMenu"
HoverCssClass="popupHover" PopupPosition="Left" OffsetX="0" OffsetY="0" PopDelay="20">
</ajaxToolkit:HoverMenuExtender>
</ItemTemplate>
<EditItemTemplate>
<table id="Table1" runat="server" visible="<%# Container.DataItemIndex == 0 %>">
<tr>
<th width="10%">
<asp:LinkButton ID="LinkButton9" runat="server" CommandName="Sort" CommandArgument="programme_name">
Programme Name
</asp:LinkButton>
</th>
<th width="10%">
<asp:LinkButton ID="LinkButton10" runat="server" CommandName="Sort" CommandArgument="Start">
Start
</asp:LinkButton>
</th>
<th width="10%">
<asp:LinkButton ID="LinkButton11" runat="server" CommandName="Sort" CommandArgument="Finish">
Finish
</asp:LinkButton>
</th>
<th width="20%">
<asp:LinkButton ID="LinkButton12" runat="server" CommandName="Sort" CommandArgument="Source">
Source
</asp:LinkButton>
</th>
<th width="20%">
<asp:LinkButton ID="LinkButton13" runat="server" CommandName="Sort" CommandArgument="Destination">
Destination
</asp:LinkButton>
</th>
<th width="40%">
<asp:LinkButton ID="LinkButton14" runat="server" CommandName="Sort" CommandArgument="BComment">
Comment
</asp:LinkButton>
</th>
<th width="40%">
<asp:LinkButton ID="LinkButton17" runat="server" CommandName="Sort" CommandArgument="Attachment">
Attachment
</asp:LinkButton>
</th>
</tr>
</table>
<!-- Add comments -->
<asp:Panel runat="server" ID="ItemContainer">
<asp:HiddenField runat="server" ID="IdHiddenField" Value='<%# Bind("ID") %>' />
<table width="100%">
<tr>
<td width="10%">
<asp:TextBox ID="TextBox0" runat="server" Text='<%# Bind("programme_name") %>' />
</td>
<td width="10%">
<asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("Start") %>' />
</td>
<td width="10%">
<asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("Finish") %>' />
</td>
<td width="20%">
<asp:TextBox ID="TextBox4" runat="server" Text='<%# Bind("Source") %>' />
</td>
<td width="20%">
<asp:TextBox ID="TextBox5" runat="server" Text='<%# Bind("Destination") %>' />
</td>
<td width="40%">
<asp:TextBox ID="TextBox6" runat="server" Text='<%# Bind("BComment") %>' />
</td>
<td width="10%">
<asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Attachment") %>' />
</td>
</tr>
</table>
</asp:Panel>
<asp:Panel CssClass="popupMenu" ID="PopupMenu" runat="server">
<asp:LinkButton ID="LinkButton1" runat="server" CommandName="Update" CausesValidation="true"
Text="Update" />
<br />
<asp:LinkButton ID="LinkButton2" runat="server" CommandName="Cancel" CausesValidation="false"
Text="Cancel" />
<br />
</asp:Panel>
<ajaxToolkit:HoverMenuExtender runat="server" TargetControlID="ItemContainer" PopupControlID="popupMenu"
HoverCssClass="popupHover" PopupPosition="Left" OffsetX="0" OffsetY="0" PopDelay="100">
</ajaxToolkit:HoverMenuExtender>
</EditItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="BookingsSQL" runat="server" ConnectionString="<%$ ConnectionStrings:BookingsConnectionString %>"
OldValuesParameterFormatString="original_{0}" ConflictDetection="OverwriteChanges"
SelectCommand="SELECT [ID], [ProgrammeName] AS programme_name, [Start], [Finish], [Source], [Destination], [BComment],[Attachment] FROM [DailySheets]"
DeleteCommand="DELETE FROM [Bookings] WHERE [ID] = @ID"
InsertCommand="INSERT INTO [DailySheets] ([programme name], [Start], [Finish], [Source], [Destination], [BComment] , [Attachment]) VALUES (@programme_name, @Start, @Finish, @Source, @Destination, @BComment)"
UpdateCommand="UPDATE [DailySheets] SET [ProgrammeName] = @programme_name, [Start] = @Start, [Finish] = @Finish, [Source] = @Source, [Destination] = @Destination, [BComment] = @BComment , [Attachment] = @Attachment WHERE [ID] = @ID">
<DeleteParameters>
<asp:Parameter Name="ID" Type="Int32" />
<asp:Parameter Name="Start" Type="DateTime" />
<asp:Parameter Name="Finish" Type="DateTime" />
<asp:Parameter Name="Source" Type="String" />
<asp:Parameter Name="Destination" Type="String" />
<asp:Parameter Name="BComment" Type="String" />
<asp:Parameter Name="programme_name" Type="String" />
</DeleteParameters>
<InsertParameters>
<asp:Parameter Name="programme_name" Type="String" />
<asp:Parameter Name="Start" Type="DateTime" />
<asp:Parameter Name="Finish" Type="DateTime" />
<asp:Parameter Name="Source" Type="String" />
<asp:Parameter Name="Destination" Type="String" />
<asp:Parameter Name="BComment" Type="String" />
</InsertParameters>
<UpdateParameters>
<asp:Parameter Name="ID" Type="Int32" />
<asp:Parameter Name="Start" Type="DateTime" />
<asp:Parameter Name="Finish" Type="DateTime" />
<asp:Parameter Name="Source" Type="String" />
<asp:Parameter Name="Destination" Type="String" />
<asp:Parameter Name="BComment" Type="String" />
<asp:Parameter Name="programme_name" Type="String" />
</UpdateParameters>
</asp:SqlDataSource>
<%# Eval("Attachment") %>
然后根据从数据库返回的值，设置图像的url。要按照SliverNinja的建议创建处理程序，可以执行以下操作。使用以下内容创建ImageHandler.ashx文件：
public class ImageHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
string id = context.Request.QueryString["id"];
if (!string.IsNullOrEmpty(id))
{
int programId = 0;
if (int.TryParse(id, out programId))
{
// Get the BLOB image from the database
var attachment = GetAttachmentImage(programId);
if (attachment != null)
{
context.Response.ContentType = "image/jpeg";
context.Response.BinaryWrite(attachment);
}
}
}
}
public bool IsReusable
{
get
{
return false;
}
}
}
<img src='ImageHandler.ashx?id=<%# Eval("id") %>' />
这段代码的输出是什么？它是否指向图像的有效URL？您应该只复制代码中不起作用的部分。也许只是查询和图像标签。实际上理论上他们可以，但这对于较大的项目是完全不明智的；但是可以将图片内联到html中。但它也比评估复杂得多。亲爱的原创海报，获取一本关于HTML如何处理图像的基本书籍，然后检查您在浏览器中创建的hre。