如何使用C#在ASP.NET中将二进制图像显示到gridview中？

Question

我想将二进制图像显示到名为'gvExistedCharacter'的网格视图中.我做过关于它的研究,其中许多建议使用处理程序.但是,我不知道我该怎么做.

仅供参考:数据库中图像的数据类型为image,名为"blueBallImage".我还想在同一个gridview中显示它的int级别.

我试过了

    SqlConnection con = new SqlConnection(@"Data Source=localhost;Initial Catalog=MyCloudGames;Integrated Security=True");

    SqlCommand cmd = new SqlCommand("Select blueBallImage FROM CorrespondingBall", con);
    cmd.CommandType = System.Data.CommandType.Text;
    cmd.Connection = con;

    SqlParameter ImageID = new SqlParameter("@characterID", System.Data.SqlDbType.Int);
    ImageID.Value = context.Request.QueryString["characterID"];
    cmd.Parameters.Add(ImageID);
    con.Open();
    SqlDataReader dReader = cmd.ExecuteReader();
    dReader.Read();
    context.Response.BinaryWrite((byte[])dReader["Image"]);
    dReader.Close();
    con.Close();

我收到错误"参数化查询"(@characterID int)选择blueBallImage FROM CorrespondingBall'需要参数'@characterID',这是未提供的."

Answer 1

您可以使用处理程序在gridview中显示图像,您的html标记看起来像在里面

Gridview ItemTemplate 将图像控制src设置为 src=~/ShowImage.ashx?id=" + id

ShowImage.ashx你的处理程序在哪里返回MemoryStream((byte [])img);

这里我的一篇类似的文章如何获取二进制数据并显示为图像

博客文章:将二进制数据转换为图像,从二进制数据保存和检索图像asp.net c#

在你的情况下你的查询字符串是 characterID

所以你的图像是src src=~/ShowImage.ashx?id=" + characterID

更新答案:

Html标记:

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:TemplateField HeaderText="CharacterID">
            <ItemTemplate>
                <asp:Label ID="lblid" runat="server" Text='<%# Bind("characterID") %>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="GameLevel">
            <ItemTemplate>
                <asp:Label ID="lblglevel" runat="server" Text='<%# Bind("gameLevel") %>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="Image">
            <ItemTemplate>
                <asp:Image ID="Image1" runat="server" ImageUrl='<%#"ShowImage.ashx?getID="+Eval("characterID") %>' />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

代码背后:

protected void Page_Load(object sender, EventArgs e)
{        
    DataTable dt = getData();
    GridView1.DataSource = dt;
    GridView1.DataBind();
  }

public  DataTable getData() 
{
  SqlDataAdapter dap = new SqlDataAdapter("select characterID,blueBallImage,gameLevel from CorrespondingBall", cn);
  DataSet ds = new DataSet();
  dap.Fill(ds);
  return ds.Tables[0];
}

通用处理程序:在这里添加新的通用处理程序showIamges.ashx是我的通用处理程序

public void ProcessRequest(HttpContext context)
 {
    Int32 my_Id;
    if (context.Request.QueryString["getID"] != null)
    {
       my_Id = Convert.ToInt32(context.Request.QueryString["getID"]);
       context.Response.ContentType = "image/jpeg";
       Stream strm = ShowEmpImage(my_Id);
       byte[] buffer = new byte[4096];
       int byteSeq = strm.Read(buffer, 0, 4096);
       while (byteSeq > 0)
        {
           context.Response.OutputStream.Write(buffer, 0, byteSeq);
           byteSeq = strm.Read(buffer, 0, 4096);
        }
      }
}

public Stream ShowEmpImage(int my_Id)
{
   string conn = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
   SqlConnection connection = new SqlConnection(conn);
   string sql = "select blueBallImage from CorrespondingBall WHERE characterID = @ID";
   SqlCommand cmd = new SqlCommand(sql, connection);
   cmd.CommandType = CommandType.Text;
   cmd.Parameters.AddWithValue("@ID", my_Id);
   connection.Open();
   object img = cmd.ExecuteScalar();
   return new MemoryStream((byte[])img);
 }