I have a datatable with 2 columns named TimeStamp and value. After I populate the table with rows, I am using the table's compute method to get the max value like this....
MyTable.Compute("MAX(value)", Nothing)
Is there is a way to get the row (or more specifically the TimeStamp value) where the max was found?
See the code below which is triggered on a datagridview row validation event where the datagridview datasource is a datatable.
The messagebox shows that it loops around as expected populating the datarow with the expected values (NOTE: There are no primary keys as this is a college assignment with specific requirement and all fields can be nullable).
I had to use ImportRows as AddRows would always error due to "This row belongs to another table" the odd thing was the values were different and again the table contains no primary keys.
The code below runs but never adds a datarow to the dataset datatable "Bookings", does anyone know what the problem might be?
CODE:
I need to round the result from compute.8/19, how can i round this result to two decimal.Is there any symbol i can use for compute function to recognize the rounding format, because not must be two decimal,sometime may one or in integer?
View 3 Repliesthis function enables you to calculate a full arithmetic calculation , as 5*(3+2)+6 , but : it's limited with (+,-,*,/) signs . is there any way to add a support for the another signs (like : !,sin,cos,tan,root,^,log and another signs) to give the user the ability to calculate a full calculation including the other signs which cannot be calculated within the compute.datatable function ?
View 2 RepliesI do have the following problem extracting records from a datatable, based on date.
I am using Datatable.compute to sum the relevant rows, at least I'm trying to!
CrTot is a variable of type double
BankTrans is a datatable
dteRecDte is a datetimepicker component
CrTot = BankTrans.Compute("sum(bank_amount)",
"bank_amount > 0 And date_bank_reconciled <="
& dteRecDte.Value.Date)
doing the sum calculation on it's own works properly. I now need to check that the date of the "date_bank_reconciled" field is less than or equal to the value of the date entered in the datetimepicker "dteRecDte.Value.Date", so that only rows with a date either less than or the same as that in the datetimepciker are returned.
I have an app that contains a DataTable that I must summarize. In that table is a Status column (also the index order) and I want to write a loop in which I compute the count for each status. So I wrote my loop and tried to use the compute function of the Datatable class, but I cannot get it working due to some constraints - specifically this...
[Code]....
You can see what I am doing here is grabbing the string value of the Status column, and then trying to get a count of how many records have that Status. My ultimate goal was to cycle the Table and count each time the status changes. But the error I get has to do with where I store the Status in a String, and then issue the second parameter on the Compute function which contains a variable (sumString) and this is where Compute is crashing - and of course, I can see why - my Status is not literal and thus not in quotes.
Generally speaking, is there any way to manage this kind of thing? In my (very) old FoxPro days one would use a macro such as "Status = &sumString" and VFP would translate sumString to its literal. I have never discovered a way to do that in .NET.
I need help with this line of code: Me.avgsalespricetxt.Text = Me.dtsold.Compute("AVG(Convert([Selling Price]),'System.Int32'))")
Here is all the code i have so far, I need to Average a column in my datatable from what i have read "Compute method supports expressions and they support CONVERT function that you could use inside of the expression."
[Code]...
I am using datatable.comput to calculate the avg of a data column. The data column's datatype = integer, so it returns a integer avg value as well. Can i make it to return double value?
View 3 RepliesI've VB.NET function that reads data from an Excel sheet and adds rows in a Datatable.
Private Function LoadDataToRows(ByVal TableName As DataTable, ByVal Header As System.Collections.Specialized.StringCollection) As Boolean
Dim HeaderDataExcel As String = String.Empty 'Data Header
[Code].....
But no data was add to the table, only emty rows.
I've VB.NET function that reads data from an Excel sheet and adds rows in a Datatable.
Private Function LoadDataToRows(ByVal TableName As DataTable, ByVal Header As System.Collections.Specialized.StringCollection) As Boolean
Dim HeaderDataExcel As String = String.Empty 'Data Header
[Code].....
I am working in vb2008. Is there a simple way to clone the contents of a datarow in a datatable into a new datarow instance that can be added elsewhere in the table. Can I create a new instance of a datarow and set it equal to an existing datarow?
View 5 RepliesI'm trying to delete the selected row in a gridview from the datatable but it seems like it's not deleting. in if statment Table.Rows.Count = 0 is not working and I'm trying this with one row in the grid view.
Protected Sub GridView1_RowCommand(sender As Object, e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles GridView1.RowCommand
Dim index As Integer = Convert.ToInt32(e.CommandArgument)
[Code].....
I have a listbox and its source is a DataTable, when i click a button i want to get the selected datarow somehow, maybe the index number of it so i can edit its values etc.
View 2 RepliesIn a web applicaion using vb.net as the code behind. I have created a DataSet (hdar) in the designer with a data table and table adapter (AccessRequests). I am trying to add a row to the database table using datatable.add row
[Code]...
This is bug in VB 2008
Dim dsExpre as New DataTable
Table has Two Fields (ExprID, Expression)
112,xyz
113,abc
Private Sub..........
Dim rsExpr as DataRow=Nothing
Dim i as Integer
[Code] .....
The Problem is, When i becomes 2, Table Data also becomes "q", Why....?
I have created a datatable and now i need to print it,so i did the following:
Private Sub PrintDocument1_PrintPage(ByVal sender As Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles PrintDocument1.PrintPage
Dim xPos As Single = 20
[CODE]...
The code works fine.But in the above code as you can see that i am printing the each rows content of the datatable one by one and after printing all the contents of a single row i am looping the code again for printing each and every row present in the datatable. So i want to know that inspite of printing each and every data present in the row of the datatable,is it possible to print the entire datarow at a time and then loop through all the rows present in the datatable?
I want to calculate variance of a col in my datatable object. If i apply datatable.compute(Var(...)), i gives a negative result. Variance can't be negative. And it I just apply it to half of the data, it works fine. Does datatable.compute has a limited capacity?
View 7 RepliesI have a column: {2,2,null}. If i use datatable.compute to compute the avg of this column, will it return 2 or 1.66? In another word, will this function ignore the null value?
View 4 RepliesIs there a way to use the DataTable.Compute Method with 2 or more filters, i have googled a bit and cant seem to come up with answer?
Current code
Dim Dt As Decimal = NumericUpDown1.Value
dtlist.Rows(i)("Value") = dtsold.Compute("Max(ClosePrice)", "Distance <=" & Dt & "")
[code].....
How can i compute the total value of a row in datagridview in vb 2008[code]...
View 4 RepliesI am retrieving the Max Value of a column using the Table.Compute Method
Max Value
dtlist.Rows(i)("Value") = dtsold.Compute("Max(ClosePrice)", "Distance <= " & Dt & " And BuildingSize<= " & GLA & "")
I would like to also return another value of that same record
How do I identify the record that is the Max Value?
I am developing a VB.net application with an Access database. I have the database connected fine to allow me edit existing customers and update the dataset and the database. However when I try to add a new customer to the database - i.e a new row it causes and error when I try to update the database. The error is
"Syntax error in INSERT INTO statement."
This is my code:
Imports System.Data
Imports System.Data.OleDb
Module Module1
Friend objConnection As New OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source = ordersystem.accdb")
[Code] .....
I think it is just a small thing which is causing this error. I have spent hours going through another example that works perfectly and I cannot find any discrepancies!
my code is
Dim rows() As Data.DataRow
rows = DataSet1.Tables(0).Select("unitname='Ltr'")
dim i as integer
for i = 0 to rows.count -1
MsgBox(rows(i).item(0)) '' HERE ERROR ITEM PROPERTY NOT FOUND
next
so i want a specific item in rows like this code we use in dataset...DSet.Tables(0).Rows(1).Item(1)
I have a table in an SQL database bound to a datagridview and am having an issue with understanding what happens when I add a new data row.
My datatable is built in code with the first column created using this sql command...
vb
cmdString = String.Format("CREATE TABLE {0} ({1} INT IDENTITY(1,1) NOT NULL, ", tableName, columnNames(0))
after that there a a number of other columns added to the command to build the table. After the table is created, I fill the datatable and bind the datagridview using this code....
vb
Dim cmdString As String = String.Format("SELECT * FROM {0}", DB_DATALOG_TABLE_NAME)
DataLogAdapter = New SqlDataAdapter(cmdString, dBConnection)
DataLogTable = New DataTable
[Code].....
This is where my understanding is falling. Because I have created the datatable's first column with the NOT NULL key word, an exception throws when I try to update the data adapter because the first column of the data row is empty By creating the table with the first column the IDENTITY key word, doesn't that imply that the database will generate the value for that column? If so, when I add a new datarow, how does the identity column get filled?
I am trying to save a row to a variable so that I can remove it from the DataTable and then add it at a different index. thing is, the row that is added is empty of the information from the data row. I'm thinking the DataRow is not saving to the variable properly. Here's my
Dim row As DataRow = dtFolderList.Rows(MoveIndex)
I'm 99.99% positive I found out how to do this like last week or soemthing but can't for the life of me remember where I found it or how to do it.
Is there a way to nest a datatable into another datatable? I know you can do this with gridviews but thats not what I'm looking for.
Also, I don't want to merge the datatables. What I'm trying to do is have a datatable with 2 columns and each column containing different datatables.
I have two datatables with similar structures that I want to make one existing row to be updated from another datatable.
For example, "tableA" has three columns: "one", "two", and "three"; with "one" being the primary key...
and "tableB" has three columns as well: "one", "two", and "three"; with "one" being the primary key.
Say there is a row on tableA that is different than a row on tableB (with a matching primary key). What I wanted to do, as efficiently as possible, is to take the that row from tableB and replace the one on tableA so it'll be modified.
I'm not sure if there's an easier way of doing that instead of using loops for setting the row's items.
im dr As DataRow = CType(Me.ProductBindingSource.Current, DataRowView).Rowbut I get the error saying:
View 15 Repliesi have a datatable with some data, i need to select some of the data, and put that data in a new datatable.
View 1 Replieshow can we compute tax using the values in the database.?
View 10 Replies