I am developing an application using Visual Basic 2010 for hydraulic calculations of a pipe network.
This application uses a lot of iterations and loops, depending on the user input and size of network. Most of the results have to be saved temporarily to be used for the next step of calculations.
Firstly, I used a DataGridView
to save the results but as the number of iterations increased, the application became very slow.
Now I am trying to create a DataTable
, then populate it with some initial results (this part was successful). The obtained DataTable
has some columns that are not populated like so:
22 24 10
3 16 22 9 15
16 12 24 13
14 21 10 23 12 1
24 18 23 2 1
Other calculations are performed and a certain value (X)
is obtained.
Now I am trying to loop through the columns of a specific row to check if the calculated value (X)
equals to one of the values in those columns.
My question is : How can I loop through only the columns that have values (avoiding the columns containing NULL
values) for a specific row?
I am a beginner in VB.net. I hope my question is clear as I didn't provide any code.
Thanks in advance for you help.
This is the initial code I used:
Results.DGVInitial.Rows.Clear()
Results.DGVFinal.Rows.Clear()
For m As Integer = 0 To NetworkLayout.DGVNetworkLayout.Rows.Count - 1
Results.DGVInitial.Rows.Add()
Next
Dim I As Integer = NetworkLayout.DGVNetworkLayout.Rows.Count - 1
Dim Sec(I), Ini(I) As Integer
Dim Hyd(I), Dia(I), Len(I) As Single
Dim Qsec(I), Qini(I), Vsec(I) As Single
Dim U(I), Y(I) As Single
Do
I = I - 1
Sec(I) = NetworkLayout.DGVNetworkLayout.Rows(I).Cells(0).Value
Ini(I) = NetworkLayout.DGVNetworkLayout.Rows(I).Cells(1).Value
Hyd(I) = NetworkLayout.DGVNetworkLayout.Rows(I).Cells(6).Value
Dia(I) = NetworkLayout.DGVNetworkLayout.Rows(I).Cells(4).Value
Len(I) = NetworkLayout.DGVNetworkLayout.Rows(I).Cells(3).Value
Dim V As Integer
V = Results.DGVRandomGen.Rows(TotalNum_Runs - 1).Cells(I).Value
Qsec(I) = 0
Dim q As Single = 0
For n As Integer = 0 To Results.DGVInitial.Rows.Count - 1
If Results.DGVInitial.Rows(n).Cells(1).Value = Sec(I) Then
q = Results.DGVInitial.Rows(n).Cells(0).Value
Qsec(I) = Qsec(I) + q
Else
Qsec(I) = Qsec(I)
End If
Next
If V = 1 Then ' if the hydrant is open
Qini(I) = Hyd(I) + Qsec(I)
Else ' if the hydrant is close
Qini(I) = Qsec(I)
End If
Results.DGVInitial.Rows(I).Cells(0).Value = Qini(I)
Results.DGVInitial.Rows(I).Cells(1).Value = Ini(I)
Results.DGVSectionDischarges.Rows(TotalNum_Runs - 1).Cells(I).Value = ini(I).ToString("F2")
Now instead of using
V = Results.DGVRandomGen.Rows(TotalNum_Runs - 1).Cells(I).Value
I would like to replace the "DGVRandomGen" with a DataTable called "DT_Random"
Like I said I am a beginner so I am not sure how to code it but it will be something like this:
For DT_Random.Rows (TotalNum_Runs - 1)
For Each col As DataColumn In DT_Random.Columns
If DT_Random.Rows(TotalNum_Runs - 1).Item(col) = I Then
Qini(I) = Hyd(I) + Qsec(I)
Else
Qini(I) = Qsec(I)
End If
Next
But I want to avoid Null values as not all columns are populated
Thanks
Maybe this will help you:
Dim myXvalue = 24
Dim myDataTable As New DataTable
myDataTable.Columns.Add("Col1")
myDataTable.Columns.Add("Col2")
myDataTable.Columns.Add("Col3")
myDataTable.Columns.Add("Col4")
myDataTable.Rows.Add(22, 24, 10, DBNull.Value)
myDataTable.Rows.Add(3, 16, 22, DBNull.Value)
myDataTable.Rows.Add(24, 18, DBNull.Value, 24)
For Each column As DataColumn In myDataTable.Columns
If IsDBNull(myDataTable.Rows(0).Item(column)) Then
MsgBox("DB Null Found At: " & column.ColumnName)
Continue For
End If
If myDataTable.Rows(0).Item(column) = myXvalue Then
MsgBox("Match: " & myDataTable.Rows(0).Item(column) & " found at " & column.ColumnName)
End If
Next column
Just a quick example, you may need to restructure it a bit, but at least it shows you how to access the values in your datatable by columns. I would do a function that passes a row index as a parameter and returns a boolean. Create two booleans inside the sub, one for dbnull existing in the row, and one for finding a matching value. If dbnull bool is false, and match value is true, then return true. Just make sure you loop all the columns and dont exit early.
If you need me to elaborate let me know.
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