Display image from a datatable in asp:image in code-behind

问题

I have a datatable which is filled from the resultset of a 1 row select statement (via a stored procedure in SQL Server 2008) and it contains a Image typed column which I store images in.

I have an asp:image control on an aspx page and i want to set the image to the corresponding field of that datatable but anything I do I can not. Please tell me how can I set the asp:image to image column of that datatable from the code behind.

回答1:

Try the Data URL scheme:

<img src="<%# ReturnEncodedBase64UTF8(Eval("ColumnA")) %>" />

protected static string ReturnEncodedBase64UTF8(object rawImg)
{
    string img = "data:image/gif;base64,{0}"; //change image type if need be
    byte[] toEncodeAsBytes = (byte[])rawImg;        
    string returnValue = System.Convert.ToBase64String(toEncodeAsBytes);
    return String.Format(img, returnValue);
}

回答2:

You could put <img src="data:image/png;base64,<BASE64 STRING>" />, so you would set the asp:image's ImageUrl property to "data:image/png;base64,xxx".

However, I suspect the browser support on this is spotty, works fine in IE9 and firefox, but I'm unsure of older browsers support for this.

An alternative I would recommend though, is to create a generic handler ashx, that reads the database and returns an image. You can check out this website on how to do it: http://www.dotnetperls.com/ashx, you would then set the ImageUrl property to this handlers address.

回答3:

Display Images from SQL Server Database using ASP.Net

aspx file

<asp:image ID="Image1" runat="server" ImageUrl ="ImageCSharp.aspx?ImageID=1"/>

cs file

protected void Page_Load(object sender, EventArgs e)
{
    if (Request.QueryString["ImageID"] != null)
   {
        string strQuery = "select Name, ContentType, Data from tblFiles where id=@id";
        SqlCommand cmd = new SqlCommand(strQuery);
        cmd.Parameters.Add("@id", SqlDbType.Int).Value
        = Convert.ToInt32 (Request.QueryString["ImageID"]);
        DataTable dt = GetData(cmd);
        if (dt != null)
        {
            Byte[] bytes = (Byte[])dt.Rows[0]["Data"];
            Response.Buffer = true;
            Response.Charset = "";
            Response.Cache.SetCacheability(HttpCacheability.NoCache);
            Response.ContentType = dt.Rows[0]["ContentType"].ToString();
            Response.AddHeader("content-disposition", "attachment;filename="
            + dt.Rows[0]["Name"].ToString());
            Response.BinaryWrite(bytes);
            Response.Flush();
            Response.End();
        }
    }
}

回答4:

Simply by using Convert.ToBase64String

        byte[] bytes = (byte[])dr["YourImageField"];
        string b64img = Convert.ToBase64String(bytes);
        Image1.ImageUrl = "data:image/jpeg;base64," + b64img;

来源：https://stackoverflow.com/questions/10143323/display-image-from-a-datatable-in-aspimage-in-code-behind

标签

ASP.NET

sql-server

datatable

code-behind