In this datatable there are no duplicates, I need the row index where column x value equals 2. I would do it like this:
Dim rowIndex As Integer = 0
For i = 0 To mtable.Rows.Count - 1
If mtable.Rows(i)("x") = 2 Then
rowIndex = i
Exit For
End If
Next
I will be calling this process multiple times per second. Is there a faster way to do this in .NET?
DataTable select could work, i think it should be faster than iterating over the collection of rows.
var index = mtable.Rows.IndexOf(mtable.Select("x = 2").FirstOrDefault());
Multiple times per second is a bit vague - tens or thousands?
You could create a hash table mapping the value of "x" to the row number:
Dim nLookups = mtable.Rows.Count - 1
Dim lookupHash As New Hashtable(nLookups)
For i = 0 To nLookups
lookupHash.Add(CInt(mtable.Rows(i)("x")), i)
Next
then
Dim rowSought As Integer = -1
If lookupHash.ContainsKey(2) Then
rowSought = lookupHash(2)
End If
Or if the range of possible values of "x" is suitable, you could use an array to map the value to the row number.
Related
I have a DataGridView in which I have transferred rows from another Form.
In my DataGridView I have three columns: the first one is name, the second is value, the third is id.
I want to hide duplicate rows with the same name and id.
How can I do this? My code is not working.
For i As Integer = 1 To Form.DataGridView1.Rows.Count - 1
If Form.DataGridView1.Rows(i).Cells(0).Value.ToString = Form.DataGridView1.Rows(i - 1).Cells(0).Value.ToString AndAlso
Convert.ToInt32(Form.DataGridView1.Rows(i).Cells(2).Value) = Convert.ToInt32(Form.DataGridView1.Rows(i - 1).Cells(2).Value) Then
Form.DataGridView1.Rows(i).Visible = False
End If
Next
You have only compared current row with current index-1 row. So, your code is not working. You need a nested loop to eliminate duplicate rows:
For i As Integer = 1 To Form.DataGridView1.Rows.Count - 1
For j As Integer = i - 1 To 0 Step -1
If Form.DataGridView1.Rows(i).Cells(0).Value.ToString = Form.DataGridView1.Rows(j).Cells(0).Value.ToString AndAlso
Convert.ToInt32(Form.DataGridView1.Rows(i).Cells(2).Value) = Convert.ToInt32(Form.DataGridView1.Rows(j).Cells(2).Value) Then
Form.DataGridView1.Rows(i).Visible = False
End If
Next
Next
Here is output
When I select/click the first 2 rows individually, I am fine. I get an error if I select/click any row after that. The error message is:
" Index was out of range. Must be non-negative and less than the size of the collection"
I added a RowIndexCount to count how many rows the application is reading, and it returns 84. What is possible wrong with it?
VB.NET
Dim rowDGVDataPhys As Integer = DGVDataPhys.CurrentCell.RowIndex
txtRowIndex.text = rowDGVDataPhys
DGVDataPhys.Rows(rowDGVDataPhys).Selected = True
DGVData.Enabled = True
DGVDataPhys.Enabled = True
Dim CountRowIndexes As Integer = 0
CountRowIndexes = DGVDataPhys.RowCount
'To capture how many total rows in the GRID.
MsgBox(CountRowIndexes) 'I found 84 rows
vDeptID = DGVDataPhys.Rows(DGVDataPhys.SelectedCells(rowDGVDataPhys).RowIndex.ToString()).Cells("DeptKey").Value
vDeptName = DGVDataPhys.Rows(DGVDataPhys.SelectedCells(rowDGVDataPhys).RowIndex.ToString()).Cells("DeptName").Value
You are indexing row using the SelectedCells collection, not the Current cells Row index...
Do this instead
vDeptID = DGVDataPhys.Rows(rowDGVDataPhys).Cells("DeptKey").Value
vDeptName = DGVDataPhys.Rows(rowDGVDataPhys).Cells("DeptName").Value
I am not familiar with using macro's, but I think that what I would like excel to perform is best handled with a macro. So I can use all the input you may have!
I have these headers;
ID Tag Pen Sex Weight Class Inside range
With 450 rows of data. Based on the distribution of the weight data, I have in two other columns (class and number) the number of rows I want to select within each class. The selected rows must have the value "Yes" in the column "Inside range".
I want to randomly select the rows, based on the number needed for each class, and copy these rows to a new sheet. It sums up to 30 rows in the new sheet.
I hope you have a suggestion how to complete this action!
can you try the following, you will need to add a reference to Microsoft Scripting Runtime library:
Const rowCount = 450
Public Sub copyRows()
Dim i As Integer
Dim j As Integer
Dim classes As Scripting.Dictionary
Dim source As Worksheet
Dim colNumber As Integer
Dim colClassName as Integer
Dim colInsideRange As Integer
Dim allSelected As Boolean
Dim randomRow as Integer
Dim sumRemaining as Integer
allSelected = False
Set source = Worksheets("YourWorksheetName")
colClassName = 6 'this is the column number where class names are entered. I am assuming 6
colNumber = 7 'this is the column number where number of rows to be selected are entered. I am assuming 7
colInsideRange = 8 'this is the column number where "Inside Range" values are entered. I am assuming 9
For i = 2 to rowCount + 1 'assuming you have a header row
classes(CStr(source.Cells(i, colClassName))) = CInt(source.cells(i, colNumber)
Next i
Do until allSelected
Randomize
randomRow = Int ((Rnd * 450) + 2) 'assuming you have a header row, + 1 if you don't
If classes(CStr(source.Cells(randomRow, colClassName))) = 0 Then
With classes
sumRemaining = 0
For j = 1 to .Count - 1
sumRemaining = sumRemaining + .Items(j)
If sumRemaining > 0 Then Exit For
Next j
allSelected = (sumRemaining = 0)
End With
Else
source.Cells(randomRow, colInsideRange) = "Yes"
classes(CStr(source.Cells(randomRow, colClassName))) = classes(CStr(source.Cells(randomRow, colClassName))) - 1
End If
Loop
'Enter your code to copy rows with "Inside Range" = "Yes"
End Sub
Sorry if there are some errors or typos, I wrote from my mobile phone.
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.
I Have about 10 (DatagridView Count may varies As per User Selected Files From 2 to 10) Datagridview ,So How can i find common value from all Datagridviews ??
Comment If you need more brief details
Below is mine but It find common from 2 -2 datagridviews
For i As Integer = 1 To dgvCont
For j As Integer = 0 To Main.DGVM(i).Rows.Count - 1
For Each Val As DataGridViewRow In Main.DGVM(i + 1).Rows
If Val.Cells(0).Value = Main.DGVM(i).Rows.Item(j).Cells(0).Value Then
Dim cm As String = Val.Cells(0).Value
If cm = "" Then
Else
Analysis.lvCmn.Items.Add(Val.Cells(0).Value)
End If
End If
Next
Next
Next
I understand that you want to set two nested loops accounting for an undetermined number of elements (items in an array of DataGridView, I presume), performing the checks you want:
For count1 As Integer = 1 To dgvCont 'Assuming indices from 1 to dgvCont
For row1 As Integer = 0 To Main.DGVM(count1).Rows.Count - 1
If (Main.DGVM(count1).Rows(row1).Cells(0).Value Is Nothing) Then Continue For
Dim val1 As String = Main.DGVM(count1).Rows(row1).Cells(0).Value
Dim found As Boolean = False
For count2 As Integer = 1 To dgvCont 'Assuming indices from 1 to dgvCont
If (count2 = count1) Then Continue For
For row2 As Integer = 0 To Main.DGVM(count2).Rows.Count - 1
If (Main.DGVM(count2).Rows(row2).Cells(0).Value Is Nothing) Then Continue For
Dim val2 As String = Main.DGVM(count2).Rows(row2).Cells(0).Value.ToString()
If val1 = val2 Then
Dim cm As String = val1
If cm = "" Then
Else
Analysis.lvCmn.Items.Add(val1)
End If
found = True
Exit For 'By assuming that you want to stop searching after finding a match
End If
Next
If (found) Then Exit For 'By assuming that you want to stop searching after finding a match
Next
Next
Next
Your code is not too clear (neither what you want); but this should give you a good enough start to carry out the implementation you are looking for. Bear in mind that this code (like yours) only considers one column (first one); in case of wanting to iterate through all the columns, you would have to add further nested loops accounting for that.