Asp.Net将图像添加到SQL表中......我做错了什么？ [英] Asp.Net Adding Images to SQL Table...What am I doing wrong?

问题描述

我以前做过这个，但方式不同。我想让下面的代码工作。如果我没有投射'OriginalPhoto'或'Thumbnail'，则会发生错误。不允许从数据类型varchar到varbinary（max）的隐式转换。使用CONVERT函数运行此查询。我不明白为什么要求演员。但是，如果我进行投射，图像就会以二进制数据格式添加到数据库中。在尝试查看图像时，我收到错误无法显示给定数据。我已经使用SqlDataAdapter将byte []插入到表中并且可以正常工作。我想使用这种方法，我做错了什么？

I have done this previously but in a different way. I am trying to get the code below to work. If I do not cast 'OriginalPhoto' or 'Thumbnail' an error occurs. Implicit conversion from data type varchar to varbinary(max) is not allowed. Use the CONVERT function to run this query. I don't understand why it asking to cast. However if I do cast it, the images add to the database just fine in a binary data format. When trying to view the images, i get the error 'Unable to display the given data'. I have inserted both byte[] into a table using a SqlDataAdapter and that works. I want to use this method though, what am I doing wrong?

PROFILEGALLERY表包含：

PROFILEGALLERY TABLE CONTAINS:

UserId nvarchar（50）

Title nvarchar（10） ）

OriginalImage varbinary（max）

ThumbImage varbinary（max）

UserId nvarchar(50)
Title nvarchar(10)
OriginalImage varbinary(max)
ThumbImage varbinary(max)

protected void AddPhotoToDatabase()
{
    byte[] OriginalPhoto = GetImage();
    byte[] Thumbnail = GenerateThumbnail();
    string Title = FileUpload1.FileName.ToString();
    string sql = "INSERT INTO [ProfileGallery] ([UserId], [Title], [OriginalImage], [ThumbImage]) VALUES ('" + User.Identity.Name + "', '" + Title + "', CAST('" + OriginalPhoto + "'AS VARBINARY(MAX)), CAST('" + Thumbnail + "'AS VARBINARY(MAX)))";
    string strCon = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["SocialSiteConnectionString"].ConnectionString;
    SqlConnection conn = new SqlConnection(strCon);
    SqlCommand comm = new SqlCommand(sql, conn);
    conn.Open();
    comm.ExecuteNonQuery();
    conn.Close();
}

protected byte[] GetImage()
{
    byte[] photo = new byte[FileUpload1.PostedFile.ContentLength];
    FileUpload1.PostedFile.InputStream.Read(photo, 0, photo.Length);
    return photo;
}

protected byte[] GenerateThumbnail()
{
    System.Drawing.Image image = System.Drawing.Image.FromStream(FileUpload1.PostedFile.InputStream);
    double thumbwidth = 0;
    double thumbheight = 0;
    double imgsz = 150.0;
    if (imgsz / image.Width < imgsz / image.Height)
    {
        thumbwidth = image.Width * (imgsz / image.Width);
        thumbheight = image.Height * (imgsz / image.Width);
    }
    else
    {
        thumbwidth = image.Width * (imgsz / image.Height);
        thumbheight = image.Height * (imgsz / image.Height);
    }
    System.Drawing.Image thumb = image.GetThumbnailImage((int)thumbwidth, (int)thumbheight, delegate() { return false; }, (IntPtr)0);
    MemoryStream ms = new MemoryStream();
    thumb.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
    return ms.ToArray();
}

推荐答案

您应该使用sql参数：

You should use sql parameters:

using( SqlConnection cnn = GetConnection() ) {
    using( SqlCommand cmd = cnn.CreateCommand() ) {
        cmd.CommandText = "INSERT INTO [ProfileGallery] ([UserId], [Title], [OriginalImage], [ThumbImage]) VALUES (@UserId, @Title, @OriginalPhoto, @Thumbnail)";
        cmd.Parameters.AddWithValue( "@UserId", User.Identity.Name );
        cmd.Parameters.AddWithValue( "@Title", Title );
        cmd.Parameters.AddWithValue( "@OriginalPhoto", OriginalPhoto );
        cmd.Parameters.AddWithValue( "@Thumbnail", Thumbnail );

        cnn.Open();
        cmd.ExecuteNonQuery();
        cnn.Close();
    }
}

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