01532e82   
   XPost: microsoft.public.dotnet.languages.csharp   
   From: arne@vajhoej.dk   
      
   On 31-07-2010 21:52, Joe Cool wrote:   
   > On Jul 31, 9:46 pm, Arne Vajhøj  wrote:   
   >> On 31-07-2010 21:41, Joe Cool wrote:   
   >>   
   >>   
   >>   
   >>   
   >>   
   >>> On Jul 31, 9:21 pm, Arne Vajhøj    wrote:   
   >>>> On 31-07-2010 20:50, Joe Cool wrote:   
   >>>>> On Jul 31, 8:41 pm, Arne Vajhøj      wrote:   
   >>>>>> On 31-07-2010 20:39, Joe Cool wrote:   
   >>>>>>> On Jul 31, 8:37 pm, Arne Vajhøj        wrote:   
   >>>>>>>> On 31-07-2010 20:29, Joe Cool wrote:   
   >>   
   >>>>>>>>> On Jul 31, 8:02 pm, Arne Vajhøj          wrote:   
   >>>>>>>>>> On 31-07-2010 19:36, Joe Cool wrote:   
   >>   
   >>>>>>>>>>> I am cross posting this request for help in both the C#,NET and the   
   >>>>>>>>>>> SQLServer newsgroups in he hope that some reader of one these   
   >>>>>>>>>>> newsgroups can offer some help.   
   >>   
   >>>>>>>>>>> I am well aware that the image datatype (as well as others) are   
   being   
   >>>>>>>>>>> phased out in some future version of SQL Server. For that reason,   
   in   
   >>>>>>>>>>> all of my personal C#.NET projects that store images use the   
   >>>>>>>>>>> varbinary(max) datatype.   
   >>   
   >>>>>>>>>>> I am in the process of converting a VB.NET project that I use for   
   >>>>>>>>>>> consulting work with a former (and hopefully soon to be repeat)   
   >>>>>>>>>>> employer tp C#.NET. When originally designed, their software was   
   based   
   >>>>>>>>>>> on SQL7. Currently their software supports SQL2005. One key table   
   in   
   >>>>>>>>>>> their database is a table of images and (not sure if it still does)   
   >>>>>>>>>>> but legacy databases utilize the image datatype to store images.   
   With   
   >>>>>>>>>>> SQL7 I used a SQL command line utility called TEXTCOPY to extract   
   the   
   >>>>>>>>>>> binary content of image columns to a JPG file.   
   >>   
   >>>>>>>>>>> This utility needs to be able to extract these images to external   
   >>>>>>>>>>> files even for legacy databases that may still use the image   
   datatype.   
   >>>>>>>>>>> But I find that the technique I use to extract images from a   
   >>>>>>>>>>> varbinary(max) column doesn't work for image datatypes. And I see   
   that   
   >>>>>>>>>>> SQL2005, while it still supports image datatype, the TEXTCOPY   
   utility   
   >>>>>>>>>>> is nowhere to be found.   
   >>   
   >>>>>>>>>>> Any ideas on how to extract image data types from a SQL2005   
   database   
   >>>>>>>>>>> with C#.NET?   
   >>   
   >>>>>>>>>> Have you tried the obvious: SqlConnection, SqlCommand, SELECT,   
   >>>>>>>>>> ExecuteReader, SqlDataReader og læse kolonnen som byte[] ?   
   >>   
   >>>>>>>>> Here is what I am using that works with varbinary(max) datatype   
   >>>>>>>>> columns.   
   >>   
   >>>>>>>>> SqlCommand cmd;   
   >>>>>>>>> SqlDataReader rdr;   
   >>>>>>>>> DataTable dataTable;   
   >>   
   >>>>>>>>> cmd = new SqlCommand("select imagecolumn, linkcolumn from images",   
   >>>>>>>>> cn)'   
   >>>>>>>>> rdr = cmd.ExecuteReader();   
   >>>>>>>>> dataTable.Load(rdr);   
   >>   
   >>>>>>>> Drop the data table and try:   
   >>   
   >>>>>>>> while(rdr.Read())   
   >>>>>>>> {   
   >>>>>>>>          byte[] image = (byte[])rdr[0];   
   >>>>>>>>          string link = (string)rdr[1];   
   >>>>>>>>          // process image and link   
   >>   
   >>>>>>>> }   
   >>   
   >>>>>>> Umm, so are you saying that while the datatable works with a   
   >>>>>>> varbinary(max) datatype, for an image datatype I should drop the   
   >>>>>>> datatable and just use a data reader?   
   >>   
   >>>>>> I don't know if the data table is the problem.   
   >>   
   >>>>>> I know that the reader will work.   
   >>   
   >>>>>> And according to your description, then you don't need   
   >>>>>> the data table.   
   >>   
   >>>>>> So it is worth a try.   
   >>   
   >>>>> The only reason I was trying to use a data table is because I am using   
   >>>>> a support class library (that I also wrote) that returns data using   
   >>>>> just a datatable. I suppose I can enhance it to also support returning   
   >>>>> data with a data reader.   
   >>   
   >>>> What is the problem when you try getting the image with the   
   >>>> current code?   
   >>   
   >>> The extracted files are smaller than the JPGs extracted by the VB.NET   
   >>> version and are not valid JPG files (their content is not the same).   
   >>   
   >> Is the size in the DB correct?   
   >>   
   >> If yes - is the size in the data table correct?   
   >   
   > In the FileStream object's Write mthod, I am using   
   > ((byte[])dataTable.Rows[i][0]).Length as the number of bytes to write.   
   >   
   > I assume thelength is the DB is correct since I am using the same DB   
   > to test the C#.NET program to test with that I originally used the   
   > VB.NET programs to originally extract the JPs with.   
      
   How does the VB.NET and C# code differ?   
      
   Arne   
      
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