ASP.NET将二进制映像绑定到转发器中的映像控制

Question

I have a simple repeater like this:

<asp:Repeater ID="repImages" runat="server" OnItemDataBound="repImages_ItemDataBound">
        <ItemTemplate>
            <asp:Image ID="Image1" runat="server" />
        </ItemTemplate>
    </asp:Repeater>

Databinding like this:

void BindImages()
    {
        string sql = @"SELECT A.*, B.* FROM ImageMetaData A
INNER JOIN ImageData B
ON A.ImageId = B.ImageId
WHERE A.CapId = @capid AND width = 250";
        SqlQuery q = new SqlQuery("imagelibrary", sql);
        q.Parameters.AddWithValue("@capid", Convert.ToInt32(ddlVehicle.SelectedValue));
        DataTable dt = q.OpenDataTable();
        repImages.DataSource = dt;
        repImages.DataBind();
    }

The datatable i've bound to has a field which contains an image as a byte array. How do I get the image control to display this:

 protected void repImages_ItemDataBound(object sender, RepeaterItemEventArgs e)
    {
        Image img = (Image)e.Item.FindControl("Image1");
        if (img != null)
        {
            img.ImageUrl = "data:image/png;base64," + ""; ???
        }
    }

Thanks

Answer 1

To convert a byte[] to a base64 encoded string, you can use th Convert.ToBase64String(byte[]) method.

Based on your code, something similar to the following should work:

protected void repImages_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    Image img = (Image)e.Item.FindControl("Image1");
    if (img != null)
    {
        if ((e.Item.ItemType == ListItemType.Item) || (e.Item.ItemType == ListItemType.AlternatingItem))
        {
            DataRowView row = e.Item.DataItem as DataRowView;

            byte[] data = (byte[])row["ImageData"]; // get your data from the row

            img.ImageUrl = "data:image/png;base64," + Convert.ToBase64String(data); 
         }
    }
}