• 将图片以二进制的方式保存在数据库中,并显示图片


    http://www.aspnettutorials.com/tutorials/database/store-img-bins-asp4-cs/

    http://stackoverflow.com/questions/18998763/how-to-retrieve-binary-image-from-database-using-c-sharp-in-asp-net

     在GridView里面显示图片,当单击这个图片的时候,放大显示这个图片

    http://www.aspsnippets.com/Articles/Display-GridView-images-with-LightBox-effect-whenever-user-clicks-on-images-in-ASPNet.aspx

    1. 创建一个数据表

    CREATE TABLE [dbo].[SaveImageByBinary]
    (
       [Id] INT NOT NULL PRIMARY KEY IDENTITY, 
        [Image] VARBINARY(MAX) NULL,    
        [ImageName] NVARCHAR(MAX) NULL
    )

     2. HTML 页面

     <div>
            <asp:FileUpload ID="FileUpload1" runat="server" />
            <asp:Button ID="Button1" runat="server" Text="SaveImage" OnClick="Button1_Click"/><hr />    //保存上传的文件
            <asp:Image ID="Image1" runat="server" /><br /> //显示图片
            <asp:Button ID="Button2" runat="server" Text="DisplayImage" OnClick="Button2_Click"/><br />  //第二种方式显示图片
            <img id="img" runat="server" alt=""/><br />
            <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label> 
        </div>


    3.将图片以二进制的方式保存到数据库

     protected void Button1_Click(object sender, EventArgs e)
            {
                
                if (FileUpload1.PostedFile != null && !string.IsNullOrEmpty(FileUpload1.PostedFile.FileName))
                {
                   
                    byte[] Image = new byte[FileUpload1.PostedFile.ContentLength];
                  
                    HttpPostedFile img = FileUpload1.PostedFile;
                    img.InputStream.Read(Image, 0, (int)FileUpload1.PostedFile.ContentLength);
    
                    SqlConnection conn = new SqlConnection(WebConfigurationManager.ConnectionStrings["DemosDatabaseConnectionString"].ConnectionString);
                    SqlCommand cmd = new SqlCommand("INSERT INTO SaveImageByBinary([Image],ImageName) VALUES (@ImgBin,@ImageName)", conn);
                    cmd.CommandType = CommandType.Text;
                    cmd.Parameters.Add("@ImgBin", SqlDbType.Image, Image.Length).Value = Image;
                    cmd.Parameters.Add("@ImageName", SqlDbType.NVarChar).Value = FileUpload1.FileName;
                    using (conn)
                    {
                        //open the connection
                        conn.Open();
                        //send the sql query to store the data
                        cmd.ExecuteNonQuery();
                        Response.Write("Succeed");
                    }
                }
                else
                {
                    byte[] Image = new byte[FileUpload1.PostedFile.ContentLength];
    
                    HttpPostedFile img = FileUpload1.PostedFile;
                    img.InputStream.Read(Image, 0, (int)FileUpload1.PostedFile.ContentLength);
    
                    SqlConnection conn = new SqlConnection(WebConfigurationManager.ConnectionStrings["DemosDatabaseConnectionString"].ConnectionString);
                    SqlCommand cmd = new SqlCommand("INSERT INTO SaveImageByBinary([Image],ImageName) VALUES (@ImgBin,@ImageName)", conn);
                    cmd.CommandType = CommandType.Text;
                    cmd.Parameters.Add("@ImgBin", SqlDbType.Image, Image.Length).Value = Image;
                    cmd.Parameters.Add("@ImageName", SqlDbType.NVarChar).Value = FileUpload1.FileName;
                    using (conn)
                    {
                        //open the connection
                        conn.Open();
                        //send the sql query to store the data
                        cmd.ExecuteNonQuery();
                        Response.Write("Succeed");
                    }
                }
            }

    4. 从数据库中取出数据并以二进制的方式显示图片(需要用一个事件调用这个方法)

       public void DisplayImage_BinaryStyle()
            {
                //connect to the db
                SqlConnection conn = new SqlConnection(WebConfigurationManager.ConnectionStrings["DemosDatabaseConnectionString"].ConnectionString);
                //sql command to select the image with id of 1
                SqlCommand cmd = new SqlCommand("SELECT * FROM SaveImageByBinary WHERE Id=@ImgId", conn);
                cmd.CommandType = CommandType.Text;
                //select the image with ImgId of 1
                cmd.Parameters.AddWithValue("@ImgId", 1);
                using (conn)
                {
                    //open the connection
                    conn.Open();
                    //send the sql query to select the image and store the results in a sqldatareader
                    SqlDataReader rdr = cmd.ExecuteReader();
                    //read the data
                    if (rdr.Read())
                    {
                        Byte[] imgData = (byte[])rdr["Image"];
                        Response.OutputStream.Write(imgData, 0, imgData.Length);
                    }
                }
            }


    5. 调用事件,显示图片

      protected void Button2_Click(object sender, EventArgs e)
            {
                Image1.ImageUrl = "SaveImageByBinary.aspx";
                DisplayImage_BinaryStyle();
            }

    --------------------------------------------------------------

    第二种方式读取数据库中的二进制数据,并进行显示图片

       protected void Button2_Click(object sender, EventArgs e)
            {
                SqlConnection conn = new SqlConnection(WebConfigurationManager.ConnectionStrings["DemosDatabaseConnectionString"].ConnectionString);
                SqlDataAdapter sda = new SqlDataAdapter("select * from SaveImageByBinary",conn);
                DataTable dt = new DataTable();
                sda.Fill(dt);
    
                foreach (DataRow row in dt.Rows)
                {
                    
                    //Get the byte array from image file
                    byte[] imgBytes = (byte[])row["Image"];
                    string ImgName = row[2].ToString();
    
                    //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
                    img.Src = String.Format("data:image/Bmp;base64,{0}"", imgString);
                    Label1.Text = ImgName;
                }
            }
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  • 原文地址:https://www.cnblogs.com/songxia/p/4053955.html
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