Reading from a DataSet

[SigmaX2]

Hey;

I'm pretty new to C#, and have succeeded in loading a deliminated text file with a code snippet I found online. It loads the data into a DataSet.

All I've been able to learn from google on getting data from DataSets focuses on putting that data into a DataGrid. I don't want a datagrid. How do I go about reading the data row by row in the code (datagrids aside... which everybody seems to be obsessed with... but my program has a console interface.)
Any assistance is appreciated.
SigmaX

 

[RhythmAddict112]

This may be a helpful link; reads utilizing SqlDataReader and throws it onto the console.

http://www.csharp-station.com/Tutorials/AdoDotNet/Lesson04.aspx

Very good resource....I learned a ton from it.

All hail the INTERWEB!

 

[SigmaX2]

Thanx for the reply.

ExecuteReader(); is exactly the method I want to use, and your link is worth bookmarking... but I still can't find anything on how to use it with a dataset. My data is loaded directly from a text file... and there is no SqlCommand object on which to use ExecuteReader();

*sigh*
Been a long day...
SigmaX

 

[chmohan]

http://msdn.microsoft.com/library/d...l/frlrfSystemDataDataSetClassReadXmlTopic.asp

 

[RhythmAddict112]

chMohan's link seems to have the info you're looking for. I won't be answering any more Q's at ~1AM after 12 hours of coding because I just can't read at that point :-/

Hope you got what need.

All hail the INTERWEB!

 

[SigmaX2]

MMkay. I'm making progress, but I'm still having troubles. When I do:

foreach ( DataTable table in loaded_chart.Tables )
{
  int i = 0;
  foreach ( DataRow row in table.Rows )
  {
    lms_table[i, 0] =  (float) row[keytext];
  }
}

('keytext' being a string with the desired column name, 'loaded_chart' being the dataset, and 'lms_table' being a float array)

I get the following error:

Unhandled Exception: System.InvalidCastException: Cannot cast from source type to destination type.

Any help? I get the same error if I just do

Console.WriteLine(row[keytext]);

Thanx again,
SigmaX

 

[chmohan]

I think You should say oRow not row

and try

int i = 0;
int l=0;
foreach ( DataRow row in table.Rows )
{
l=table.Rows.Index;
lms_table[l] = (float) row[keytext];
}

 

[SigmaX2]

Okay, I've made some more progress. I have the data entering into the array now. But now the foreach() statement is executing once through, then terminating in the same error I was getting above (I dunno, maybe that was the problem in the first place).

Any clues? I fear I'm totally lost now.

 

[chmohan]

In one of the tables keytext is not a column seems to me

 

[SigmaX2]

That's what I figured at first too. But it executes the block successfully once, and throws the exception the second time it comes to the row[keytext] line.

What did you mean earlier when you said use oRow instead of row? Is it of any significance?
Thanx,
SigmaX

 

[chmohan]

Okay
use try catch block and use the exception object errormessage and source properties to get more info

 

[chmohan]

You know when you loop again and again you have to clear the array each time dont u?Or reinitialize it?

 

[SigmaX2]

No, I guess i didn't know that. Clue me in with a little explanation, because from what I can tell that's my problem.

I can get the data into a Console.Write now (Dunno why I couldn't before), but when I try to put it into my global array it goes haywire.
Thanx,
SigmaX

 

[chmohan]

you see when u first populate the array it has elements when it does the loop and next time you try to set it again you have to clear it before setting value again

 

[SigmaX2]

Mmkay... so how do I do that and preserve my data? I'm not sure I really understand what you mean. (Forgive my ignorance).
SigmaX

 

[chmohan]

http://www.mastercsharp.com/India/Forums/ShowPost.aspx?PostID=32