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Solved: I realized I'm a huge dummy and forgot a transaction I wrapped around delete operation. Turns out I forgot to add a trans.Complete() at the end of it. I added it and problem solved.
I have a typed DataSet mapping a local SQL Server CE 3.5 .sdf file using DataGridView on a WinForm. I can successfully add and modify data but for some reason I can't delete any. I don't get any errors either. Can you please give me any ideas about what could be wrong? I can't figure this out and I'd appreciate any help.
I use simple methods like this:
fill
myTableTableAdapter.Fill(myDataSet.MyTable);
add
(after adding new row to grid also to bindingsource)
myTableTableAdapter.Update(myDataSet.MyTable);
delete
myDataSet.MyTableRow row = myDataSet.MyTable.FindByID(id);
row.Delete();
myTableTableAdapter.Update(myDataSet.MyTable);
The row is gone from gridview. I also check myDataSet.MyTable parameter in myTableTableAdapter.Update(myDataSet.MyTable) using debug visualizer, it's is gone from there too (row status: Deleted). But when I refill data from database, it's back like nothing happend..
I checked DeleteCommand of the myTableTableAdapter, it is defined and correct.
I don't copy project database file over the newer build file either.
I wrote a simple log to see the rowstatus of the row. Everything seems to work as it should but still the row comes back after a db refill:
Log: row status: Unchanged
Log: calling row.Delete()
Log: row status: Deleted
Log: entering Update() function
Log: row status: Deleted
Log: calling tableAdapter.Update(dataset.Table)
Log: row status: row not found in dataset
Any ideas?
modified on Tuesday, May 26, 2009 6:12 AM
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Does the delete work in T-SQL?
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Yes I can delete with sql. I added a query to table adapter and I can delete records using it. However I'm trying to create a fully disconnected application so I really would like to solve this delete problem.
Any ideas?
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Alright, problem solved. I realized I'm a huge dummy and forgot a transaction I wrapped around delete operation. Turns out I forgot to add a trans.Complete() at the end of it. I added it and problem solved.
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Hi,
I am wanting to learn a little about how a program saves data ie saved files for a game or a program. Is there a link anyone can recommend so I can learn how to create a professional file type that i can use in my program?
I also have a program linguata that i am using to learn a foreign language. The way the program works is that it has a basic file structure and for each different language it has an ogg file (containing all the sound data) and another "lesson" file that has the word/phrase in english and the other language. it also has the specific time that the word/phrase appears in the ogg file. I want to be able to de-construct the "lesson" file so i can get the raw data for the program. with this i want to create word games to help me learn.
the file is located http://rapidshare.com/files/237060596/lesson[^]
is it possible to read it in anyway or is it encrypted?
thanks
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Hi I like file types (yea I know that's strange, but really, I do) and in particular, decoding unknown file types. So therefore I will break the rule of not downloading strange files and dive right in.
This file doesn't look encrypted, so that's good.
And I'm using XVI32 to open it, btw. I suppose there are better hex editors but I kinda grew up with it..
So, the structure. After a little header (which only seems to contain a version number) there comes a big part of 64byte structs. I can't really say much about them without having a second file of the same type to compare it with though.
But there are some things I can say. It definitely starts with an int, but I can't say what it means (could be a pointer to a record somewhere in an other section of the file). At first it seems to be rising, but that quickly stops. Then an other int, which is usually zero. Then an other int, which does seem to consistently rise (could be the time in the ogg file? a pointer into one of the records in an other section of the file?). Then just a bunch of zero's and the language name, it seems.
Then after a whole bunch of zero's, there are pairs of words + translation. Looks like 16bit unicode. The records seem to have a fixed length of 164 bytes (so 82 chars, but most of them are \0)
More zero's.. (do they waste space on purpose or what?)
Then some untranslated words? strange
More zero's..
Some rising numbers? Fun, I guess. Don't know what they do.
More zero's..
It ends with some data that doesn't look particularly useful..
And a footer ": MMG " (possibly without the ":")
It could turn out to be completely different of course.
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GREAT! Thanks
Two Questions though:
first. ok so now I can see a readable version of the data how do i get access to it? how can I read it with C#?
and second. The first bit of my original question. How do i make a file type myself. I have been using BinaryReader and giving the file the extension I like but it is easy to view the file again in paint. I want my filetype to be professional so it really shouldnt I shouldnt be able to read it in paint. Do you know of a link with an example project?
Any ideas
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I would read it with a BinaryReader
What do you mean in paint? MS paint? You can trick it to load an exe if you wanted..
The structure of this file was not especially "professional", in fact, it just sucks. Sure it gets the job done - it saves the data. But file structures for Real Programmers contain funny data structures - heaps, trees, length-prefixed blocks, whatever you want except fixed length strings (they just waste space).
There has also been a growing trend towards splitting your data in logical parts (if there is more than 1), zipping them all together, but giving it a custom extension (not .zip). Even .docx and .odt work this way. As a bonus it compresses your data so you can make the most ridiculously space wasting format you want and get away with it.
"Nice" formats to look at to get an idea are (for example) png and bzip2
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sorry I meant c# not paint. dont know why i wrote that!
Can you give me an idea how I can read the data with C#? or is there a way to output to a format that I can use with c#?
Regarding the other question. I have a simple datatable that I want to save to a file. How should I do this.
Thanks for the help.
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1) use BinaryReader
2) use BinaryWriter
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i am trying to with the following code:
OpenFileDialog fd = new OpenFileDialog();
if (fd.ShowDialog() == DialogResult.OK)
{
FileStream streamR = new FileStream(fd.FileName, FileMode.Open);
BinaryReader r = new BinaryReader(streamR);
int count=0;
while (true)
{string st=r.ReadString();
if ((count > 374855)&&(st != string.Empty))
MessageBox.Show(count+"|"+st+"|");
count++;
}
}
I am not getting anything i can read. Any ideas?
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ReadString expects a crazy string format that no one uses except WriteString in BinaryWriter
You could read a byte array and use Encoding.UTF16.GetString(bytes) or something like that
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ok still no luck I tried the code below:
OpenFileDialog fd = new OpenFileDialog();
if (fd.ShowDialog() == DialogResult.OK)
{
// fd.FileName;
//
FileStream streamR = new FileStream(fd.FileName, FileMode.Open);
BinaryReader r = new BinaryReader(streamR);
int count=0;
while (true)
{byte[] st=r.ReadBytes(8);
if ((count > 374855) && (Encoding.UTF8.GetString(st)!=string.Empty))
MessageBox.Show(count + "|" + Encoding.UTF8.GetString(st) + "|");
count++;
}
}
I used UTF8 because there wasnt a UTF16.
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Hm.. try Encoding.Unicode?
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no that doesnt work either.
is this correct in my code?
byte[] st=r.ReadBytes(8);
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It depends on the place. GetString might not like too many zero's so it might be good to remove them..
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I really have no idea. Do you think you would be able to get it to work and share the code with me?
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Ah I don't know, have you tried looking at what the byte array contains before stringing it? Probably.. but.. what was in it?
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Thanks for all your help. I was able to get the code for a c# hex editor and it helped me figure it out.
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Hi Guys,
I want to insert in a list view all the Table Names from a Oracle DB. I started by learning how from Syed M Hussain 's post :
A Very Simple Oracle Query Tool[^]
<br />
using Oracle.DataAccess.Client;<br />
using Oracle.DataAccess.Types;<br />
.....<br />
static private OracleConnection orcCon;<br />
private static OracleCommand cmd;<br />
private static OracleDataAdapter da;<br />
private static OracleCommandBuilder cb;<br />
private static DataSet ds;<br />
private static String sql;<br />
.....<br />
public static DataTable GetUserTables()<br />
{<br />
sql = "SELECT TABLE_NAME FROM USER_TABLES";<br />
cmd = new OracleCommand(sql, OrcCon);<br />
cmd.CommandType = CommandType.Text;<br />
da = new OracleDataAdapter(cmd);<br />
cb = new OracleCommandBuilder(da);<br />
ds = new DataSet();<br />
da.Fill(ds);<br />
<br />
return ds.Tables[0];<br />
}<br />
...........<br />
dtTable = Code.ConectareOracle.GetUserTables();<br />
for (int i = 0; i < dtTable.Rows.Count; i++)<br />
{<br />
MessageBox.Show(dtTable.Rows[i].ToString());<br />
}<br />
....<br />
..and the error i get is that da.Fill(ds) has : "Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
Any ideea?
Kind regards,
Alex
“Be the change you want to see in the world.”
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use Query
"select * from tab where TABTYPE='TABLE'"
instead of "SELECT TABLE_NAME FROM USER_TABLES"
the problem may be , your user don't have the sufficient previlizes.
Rajesh B --> A Poor Workman Blames His Tools <--
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Hi all,
I want to Watermark(Overlay) an existing video. I don't want to
capture a new Video . For that I m using DirectShowLib DxText Sample
Application(in C#) for VideoWatermarking on an existing video.
It works fine but it only display the video with watermark as a
preview on screen.
Now I need to save the watermarked video on the disk as a new file.
How can I do this?
Thanks in Advance
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This is no C# question.
You should better read the documentation of the component or ask this question in their forum.
Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.
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how can we save exist information in a database table using datagridview with foreach rule?
foreach (DataGridViewRow ro in (dataGridView1.Rows))
{
???????  
}
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Why do you want to use the for each loop to do this? 
Look for the existing implementations .Net provide to update the database. For eg. dataset.update
Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.
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