Help with DataSet and Select

[Elip]

Hello.

 

I�m trying to select an entry from a child row in my data set but not having any experience with data bases and the .Net DataSet I'm having some problems.

 

The data set schema is very simple; I have a primary element named DIRECTORY which contains a name field and a file field.

The file field is an element named FILE which contains its own name field and several file properties fields.

 

So, after the data set is filled I try to access a file record in the following way.

 

// this line works

DataRow *foundDirRows[] =

dataset->DIRECTORY->Select("name = '{0}'", fileInfo->Directory->Name);

 

// assum the dir is found for this example

dirRow = __try_cast<FileInfoDataset::DIRECTORYRow*>(foundDirRows[0]);

 

// this is the problem line, it never finds the file

DataRow *foundFileRows[] = dirRow->Table->Select("name = '{0}'", fileInfo->Name);

 

If I save the data set as XML and open it in Visual Studio I can clearly see that the file entry is there and it is a child of the directory I selected.

 

Apparently this is not the correct way to access the row associated with the file.

 

:confused: How should I be doing this?

[Nerseus]

I've not tried this in C++, but if it's the same type of Select as other languages, you'll want to change your Select line to this:

DataRow *foundDirRows[] = 
dataset->DIRECTORY->Select(String->Format("name = '{0}'", fileInfo->Directory->Name));

 

Normally the Select method's first param, a string, is the filter. The second param is a sort. It appears as though you really want to use String.Convert to piece together your filter.

 

-Nerseus

[loyal]

examine this code

 

Dim strExpr As String
Dim strSort As String
Dim expressions As Integer = CInt(Me.txtSearch.Text)
strExpr = "MilitryNumber =" & expressions
strSort = "MilitryNumber"


' Get a reference to the Main table.
Dim dtEmp As DataTable = DsMain1.Tables("Main")

' Copy only the structure of the Main table in the new table.
Dim newDt As DataTable = dtEmp.Clone()
newDt.TableName = "MN"

' Select a subset of all Main, sorted on their MilitryNumber.
Dim drows() As DataRow = dtEmp.Select(strExpr, strSort)

' Import the array of DataRows into the new table.
Dim dr As DataRow



 For Each dr In drows
 newDt.ImportRow(dr)
 Next

 Me.DGMain.DataSource = newDt

               
Me.DGMain.Refresh()