Comparing one dataset to another dataset in vb.net - vb.net

Question

I have two data set in my code. I need to compare that second data set
with first data set My first data set returns this result below:-
FirstDs:-
MaxUpdatedPrepped MaxUpdatedSent MaxUpdatedStamped
1900-01-01 1900-01-01 1900-01-01
And my second data set returns below:-
SecondDS:-
MaxUpdatedPrepped MaxUpdatedSent MaxUpdatedStamped
1900-01-01 1900-01-01 2014-11-11
I need to compare that both result and return alert like "Not matched" if the both first data set value is not match with second data set value. I tried a lot but i could get only wrong answer
For i As Integer = 0 To DsMaxDates1.Tables(0).Rows.Count - 1
Dim found As Boolean = False
For j As Integer = 0 To ds.Tables(0).Rows.Count - 1
If DsMaxDates1.Tables(0).Rows(i)(0).ToString = ds.Tables(0).Rows(j)(0).ToString Then
found = True
End If
Next
If found = False Then
ASPNET_MsgBox("Another User Working in Same Account. Please Click Reset.")
End If
Next
This above result returns true instead of false.

Answer 1

You should never change the type of your data unless it's absolutely necessary. Treat dates as Date, integers as Integer, strings as String, decimals as Decimal, etc. The ToString method is mostly used when you want to display the data to the user.
With that being said, you're not comparing datasets, you're comparing datatables.
The reason as to why it returns True is because you only compare the first column. You need to compare all the columns. If your table doesn't contain complex data types like byte arrays then the simplest way is to use LINQ combined with Enumerable.SequenceEqual.
The following code assumes that each table contains the same number of rows and columns.
''Uncomment to unleash the one-liner:
'Dim notEqual As Boolean = (From i As Integer In Enumerable.Range(0, DsMaxDates1.Tables(0).Rows.Count) Where (Not DsMaxDates1.Tables(0).Rows(i).ItemArray.SequenceEqual(ds.Tables(0).Rows(i).ItemArray)) Select True).FirstOrDefault()
Dim notEqual As Boolean = (
From i As Integer In Enumerable.Range(0, DsMaxDates1.Tables(0).Rows.Count)
Where (Not DsMaxDates1.Tables(0).Rows(i).ItemArray.SequenceEqual(ds.Tables(0).Rows(i).ItemArray))
Select True
).FirstOrDefault()
If (notEqual) Then
ASPNET_MsgBox("Another User Working in Same Account. Please Click Reset.")
End If
You can expand this even further by creating a reusable extension method:
Public Module Extensions
<System.Runtime.CompilerServices.Extension()>
Public Function SequenceEqual(table1 As DataTable, table2 As DataTable) As Boolean
Return (((((Not table1 Is Nothing) AndAlso (Not table2 Is Nothing))) AndAlso ((table1.Rows.Count = table2.Rows.Count) AndAlso (table1.Columns.Count = table2.Columns.Count))) AndAlso ((table1.Rows.Count = 0) OrElse (Not (From i As Integer In Enumerable.Range(0, table1.Rows.Count) Where (Not table1.Rows(i).ItemArray.SequenceEqual(table2.Rows(i).ItemArray)) Select True).FirstOrDefault())))
End Function
End Module
Then you can simply do as follows:
If (Not DsMaxDates1.Tables(0).SequenceEqual(ds.Tables(0))) Then
ASPNET_MsgBox("Another User Working in Same Account. Please Click Reset.")
End If