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."
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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...
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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 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 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 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?
I 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 RepliesI am finding difficulties to convert a datatable to a new datatable using a reference datatable. My question is confusing and I am not good at explaining things so I drew a picture (see below).I have two datatables on memory and I need to create the third datatable using the second mapping table for reference. The column names are just for example and it can't be hardcoded.
View 2 RepliesI used this code:
Code:
Friend Sub PopulateCB(ByRef mycontrol As ComboBox, _
ByVal expressionSQL As String)
' DMBD is my data-handling class:
[code]...
Nevertheless, mycontrol remains empty after this.
I have a datagridview which is populated from a datatable. This works fine. But if i run it more then once i get a column name "example" already belongs to this datatable. Ive tried everything to clear all the columns of the datatable and the gridview but still the same
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I have one specific problem, that is relative to DataTable Updates to Database.
Code:
auxDatatable = Mydataset.MyDatatable.GetChanges
Now i'm going to Accept or Reject Changes based on some Criteria. The problem is that I wish to Update Only the Records that in Fact exist on the Database, as you can imagine I was forced to create some Dummy Records in Datatable, to a specific job.
My approach to this issue was to do something like this :
Code:
Private Sub MySub (ByVal auxDatatable As DataTable)
Dim drView As Mydataset.Mydatatable
For i As Integer = 0 To auxDatatable.Rows.Count - 1
[CODE]...
As you can see I tried to Delete the rows that are Dummys, but the rows in fact are not being deleted. As consequence I get an error after that Sub, when i try to make :
Code:
MyTableAdapter.Update(auxDatatable)
This is naturaly caused by the dummy Records.
I have an application where I would like to allow the user to change one field in a datatable but leave the other ones uneditable. I am using a datagridview to do this but I can only make the whole table editable or not. The result should be an order form where you have a determined product and should only be able to change the number of items.
View 2 RepliesI am trying to summarize a datatable based on a primary column and then add certain columns. For example this table
col-1 col-2 col-3
1 AA 2
2 BB
[Code].....
This simply doesn't do anything becuase it thinks the target table doesn't have a primary key.
There is a class in this datalayer that subclasses System.Data.Datatable. So for example if I populated a System.Data.Dataset and then tried to put the first table of this dataset into this class like so:
Code:
Dim dt as new myDatable
dt = ds.Tables(0)
[code]....
I am trying to search a datatable using a compound key. I can create the compound key just fine, but when I go to create an object to pass to the find it give me an error. Below is a sample of my code.
dim lblDT...etc...
Here is where I create the compound key, and it seems fine.
lblDT.PrimaryKey = New DataColumn() {
lblDT.Columns("serialno"), _
lblDT.Columns("type")}
This is where I am trying to create an object to pass to the .find
dim objSearch As New Object() {10643, 28}
It if would work this is how the find would be.
Dim row As DataRow = lblDT.Rows.Find(objSearch)
I have been having trouble finding a good way to do this. Basically what I need to do is take a query from a SQL Server Database and place it into a DataTable (or an array) for manipulation. I've got the connection and everything working, but none of the methods I've tried so far seem to work very well.I need it to compare data with an uploaded CSV file and post on a website.
View 1 RepliesProbably a very dumb question but I have a program whereby I create and populate an in memory datatable, which I then add to a data-set. I then run a couple of updates on the dataset and need to know how to then send these updates down into the in memory datatable :Here is a mock up of the code structure following the creation and population of the table :
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I'm retooling an app, and condensing my queries down to one, but to do so, I would like to move the columns for better presentation. I am reporting on errors for particlular equipment, and the user may want to get equipment by errors or errors by equipment. Is there any way to change column order?
View 5 RepliesSource: DataTable
Destination: Access Database Table
I should mention that the DataTable contains data resulted by an SQL SELECT query and it's not related to the "targeted" Access Database Table.
i have the sql code (exported from mysql) as
[Code]...
I have tried multiple times to get string str to = this but it never works? can someone look at it and tell me wat cud be wrong or even better and possibly convert it into the str 4 me or give me an easy way to do it?
I have read many posts on this topic; among them and most recently .NET - Convert Generic Collection to Data Table. Unfortunately, all to no avail.
I have a generic collection of structures :
Private Structure MyStruct
Dim sState as String
Dim lValue as Long
Dim iLayer as Integer
End Structure
Dim LOStates As New List(Of MyStruct) I need to fill a DataTable with this list of structures but have no idea how to go about doing this. I am using vb.net in Visual Studio 2008.
Whilst programming my website offline I had the Access DB use the default value to Date() saving me a job at programming stage - it put these dates as US Format MM/dd/YYYY.Now I have uploaded it and the server uses proper UK format dd/MM/YYYY I need to change the old records under a field Date in tblItems to the UK format
View 4 RepliesI'm trying to convert DataTable to Linq using
DIm result = From r in dt.AsEnumerable()
Select new ( col1 = r.Field<integer>("id"), col2 = r.Field<string>("desc"))
But i get error near 'new (' saying type expected.
I have seen many examples of populating a listview from a datatable or converting a datatable to a listview but what I am trying to do is exactly the other way around.
How can I convert/copy the contents of a winform listview to a datatable?
[EDIT]
I have a listview with a context menu where users can multiselect items and choose one of the context menu options, I then loop the selected items and extract each selected row (listview item) and serialize it, instead of doing this I wanted to convert the listview to a datatable then add the datatable to a dataset and serialize the dataset.
convert a dataTable to List(of T).In Vb.net on .Net 3.5 If you know How To or maybe a link of somebody who did it.I check this on c# (from another stack question)
public static IEnumerable<T> ToEnumerable<T>(DataTable dt, Func<DataRow, T> translator)
{
foreach(DataRow dr in dt.Rows)
{
[code]....
but I cant translate Func on .net 3.5?
I am trying to import a large array of integers stored as a csv file into a VB.Net DataTable called BeamMap. The .csv file consists only of integers, with a delimiter of ,, no quotes around the data (ie., 1,3,-2,44,1), and an end of line character of line feed and carriage return. All I want to do is get each integer into a DataTable cell with the appropriate rows and columns (there are the same number of columns for each row) and be able to reference it later on in my code. I really don't want anything more than absolutely necessary in the code (no titles, captions, headings, etc.), and I need it to be fairly efficient (the csv array is approx. ~1000 x ~1000).
View 2 RepliesI managed to Convert a Datagridview to Datatable, Now problem is the programmatically addded Columns Seem to end up at the end of the of the initial table layout[code]...
View 2 Repliesi am using following code to convert xml file to datatable but its just creating multiple tables (but without data) and i want tables with data..
Dim myDS As New DataSet
Dim xmlStream As System.IO.StreamReader = New System.IO.StreamReader(Server.MapPath("~xmldoc
esult_availhotel.xml"))[code].....