如何在 ASP.NET 中使用 C# 从数据库中检索二进制图像
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How to retrieve binary image from database using C# in ASP.NET
提问by Liu Jia Hui
I need to retrieve a binary image from the database.
我需要从数据库中检索二进制图像。
My queries are as below.
我的查询如下。
SqlConnection con = new SqlConnection(@"Data Source=localhost;Initial Catalog=MyGames;Integrated Security=True");
SqlCommand cmd = new SqlCommand("Select blueBallImage from CorrespondingBall WHERE objective = Default Ball", con);
I do not know how to retrieve blueBallImage which is a binary image.
我不知道如何检索 blueBallImage 这是一个二进制图像。
After I have retrieve it successfully, I need to add a text onto the image using a dropdownlist which contain the text. The codes are as below.
成功检索后，我需要使用包含文本的下拉列表将文本添加到图像上。代码如下。
Bitmap bmp = new Bitmap(@"C:\Users\apr13mpsip\Documents\Visual Studio 2012\WebSites\CorrespondingBallWebSite\Images\blueBallDefault.png");
For the time being, I do not know how to retrieve the image. Therefore, I hard coded it which I do not want. I want to retrieve it from database.
目前，我不知道如何检索图像。因此，我对其进行了硬编码，这是我不想要的。我想从数据库中检索它。
Graphics gra = Graphics.FromImage(bmp);
gra.DrawString(ddlCharacter.Text, new Font("Verdana", 18), Brushes.Black, new PointF(4, 6));
MemoryStream ms1 = new MemoryStream();
bmp.Save(ms1, ImageFormat.Png);
var base64Data = Convert.ToBase64String(ms1.ToArray());
imgImage.ImageUrl = "data:image/png;base64," + base64Data;
采纳答案by Mehdi Bugnard
Here is a basic sample to load an image from database quickly and load into a html image source in ASP. Please tell me if it works for you ;-)
这是一个快速从数据库加载图像并加载到 ASP 中的 html 图像源的基本示例。请告诉我它是否适合你;-)
//Get byte array from image file in the database with basic query
SqlDataAdapter myAdapter1 = new SqlDataAdapter("Select [logo] FROM [dbo].[tblCompanyInfo]", GlobalUser.currentConnectionString);
DataTable dt = new DataTable();
myAdapter1.Fill(dt);
foreach (DataRow row in dt.Rows)
{
// Get the byte array from image file
byte[] imgBytes = (byte[]) row["logo"];
// If you want convert to a bitmap file
TypeConverter tc = TypeDescriptor.GetConverter(typeof(Bitmap));
Bitmap MyBitmap = (Bitmap)tc.ConvertFrom(imgBytes);
string imgString = Convert.ToBase64String(imgBytes);
//Set the source with data:image/bmp
imgLogoCompany.Src = String.Format("data:image/Bmp;base64,{0}\"", imgString);
}
回答by Sain Pradeep
you need to made an ASP.NET handler (*.ASHX) that serves the bytes of the image
您需要制作一个 ASP.NET 处理程序 (*.ASHX) 来处理图像的字节
<img src="ImageHandler.ashx?id=<%=id%>" />
In image handler you need to code like this
在图像处理程序中，您需要像这样编码
public class ImageHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
// Load the image (see previous code sample)
byte[] data = Convert.FromBase64String(encodedString);
// Display the image
context.Response.OutputStream.Write(data, 0, data.Length);
context.Response.ContentType = "image/JPEG";
}
}
please refer this for more info Image from Database
请参考此了解更多信息来自数据库的图像
回答by Sudhanshu Kumar
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
Connect();
}
try
{
cm = new SqlCommand("select profile_pic from TblNewMemberRegistration where user_name='[email protected]'", cn);
byte[] b = (byte[])cm.ExecuteScalar();
stream.Write(b, 0, b.Length);
Bitmap bm = new Bitmap(stream);
Response.ContentType = "image/gif";
bm.Save(Response.OutputStream, ImageFormat.Gif);
}
catch(Exception ex)
{
Response.Write(ex.Message);
}
finally
{
cn.Close();
stream.Close();
}
}
protected void Connect()
{
cn = new SqlConnection(ConfigurationManager.ConnectionStrings["connect"].ConnectionString);
cn.Open();
}
