Question

如何使用vb.net从数据库中检索二进制图像并将图像插入到GridView中。

这是我的数据库

image（id为整数，img为varbinary（max））

Answer 1

在澄清您所指的gridview的类型时，以下是如何在数据库中插入数据：

Using c As New SqlConnection(ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString)
   c.Open()
   Dim command = New SqlCommand("INSERT INTO yourtable(image) values (@image)", c)
   ' this is specific to the FileUploadControl but the idea is to get the
   'image in a byte array; however you do it, it doesn't matter
    Dim buffer(FileUpload1.PostedFile.ContentLength) As Byte
    FileUpload1.PostedFile.InputStream.Read(buffer, 0, buffer.Length)
    command.Parameters.AddWithValue("@image", buffer)
    command.ExecuteNonQuery()    
End Using

假设您正在讨论ASP .NET应用程序，可以按如下方式将数据绑定到gridview：

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
            DataKeyNames="id" DataSourceID="SqlDataSource1">
            <Columns>
                <asp:TemplateField>
                    <ItemTemplate>
                     <!--Trick to encode the bytes as a BASE64 string-->
                    <img width="100px" height="100px" src='data:image/png;base64,<%#System.Convert.ToBase64String(Eval("image"))%>' />
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
            ConnectionString="Data Source=Your_ConnectionString_GoesHere" 
            ProviderName="System.Data.SqlClient" 
            SelectCommand="SELECT [id], [image] FROM [your_table_name_goes_here]">
        </asp:SqlDataSource>

如何从vb.net中的数据库中检索二进制图像并在网格视图中插入图像

1 个答案: