显示存储在数据库 asp.net 中的图像

Question

这是我的数据库：

 create table images 
(
 ID int primary key identity, 
 Name nvarchar(255),
 Size int, 
 ImgData varbinary(max) 
)

CREATE PROCEDURE UploadImages
 @Name nvarchar(255),
 @Size int,
 @ImgData varbinary(max),
 @NewId int output
AS
BEGIN
   INSERT INTO images
     VALUES (@Name, @Size, @ImgData)

SELECT @NewId = SCOPE_IDENTITY()    
END

Create procedure spGetImageById 
@ID int
as
Begin
Select ImgData
from images where ID=@ID
End

这是我在管理页面中的代码，我编写它以将图像保存在数据库中，并且超链接似乎可以在另一个页面中看到图像以确保它是正确的图像：

HttpPostedFile PostedFile = FileUpload1.PostedFile;

string fileName = Path.GetFileName(PostedFile.FileName);
string fileExtension = Path.GetExtension(fileName);
int fileSize = PostedFile.ContentLength;

if(fileExtension.ToLower() == ".jpg" || fileExtension.ToLower() == ".bmp"|| fileExtension.ToLower() == ".gif" || fileExtension.ToLower() == ".png")
 {
  Stream stream = PostedFile.InputStream;
  BinaryReader binaryReader = new BinaryReader(stream);

  byte[] bytes = binaryReader.ReadBytes((int)stream.Length);

  string cs = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;

  using (SqlConnection con = new SqlConnection(cs))
    {
       SqlCommand cmd = new SqlCommand("UploadImages", con);
       cmd.CommandType = CommandType.StoredProcedure;

       con.Open();

     SqlParameter paramName = new SqlParameter()
     {
         ParameterName = "@Name",
         Value = fileName
     };
     cmd.Parameters.Add(paramName);

     SqlParameter paramSize = new SqlParameter()
     {
         ParameterName = "@Size",
         Value = fileSize
     };
     cmd.Parameters.Add(paramSize);

     SqlParameter paramImgData = new SqlParameter()
     {
         ParameterName = "@ImgData",
         Value = bytes
     };
     cmd.Parameters.Add(paramImgData);

     SqlParameter paramNewId = new SqlParameter()
     {
         ParameterName = "@NewId",
         Value =-1,
         Direction = ParameterDirection.Output
     };
     cmd.Parameters.Add(paramNewId);

     cmd.ExecuteNonQuery();
     con.Close();

     Lmas.Visible = true;
     Lmas.Text = "done";
     Lmas.ForeColor = System.Drawing.Color.Green;
     HyperLink1.Visible = true;
     HyperLink1.NavigateUrl = "~/ShowImage.aspx?Id=" + cmd.Parameters["@NewId"].Value.ToString();
    } 
} 
  else 
  {
    Lmas.Visible = true;
    Lmas.Text = "only images (.jpg .png .gif .bmp) can be uploaded";
    Lmas.ForeColor = System.Drawing.Color.Red;
     HyperLink1.Visible = false;
   }

我写这篇文章是为了对图像进行评论：

    string cs = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
      using (SqlConnection con = new SqlConnection(cs))
     {
          SqlCommand cmd = new SqlCommand("spGetImageById", con);
         cmd.CommandType = CommandType.StoredProcedure;

        SqlParameter paramID = new SqlParameter()
        {
            ParameterName = "@ID",
            Value = Request.QueryString["ID"]
        };
        cmd.Parameters.Add(paramID);

        con.Open();
        cmd.ExecuteScalar();
        byte[] bytes = (byte[])cmd.ExecuteScalar();
        string strBase64 = Convert.ToBase64String(bytes);
        Image1.ImageUrl = "data:Image/png;base64," + strBase64;
        }

我想在我的主页中的 img-tag 中显示图像。 所以我试图将让您查看图像的代码复制到我的主页中，但它说：“过程或函数'spGetImageById'需要参数'@ID'，但未提供”。

Answer 1

确保获取所有字节，尝试替换

string strBase64 = Convert.ToBase64String(bytes);

与

string strBase64 = Convert.ToBase64String(bytes, 0, bytes.Length); 

Image一词也改为小写：

Image1.ImageUrl = "数据:图像/png;base64," + strBase64;