I have a datatable and I would like to get the MAX number from this table where Term Number (first Column) is a certain value. If my datatable is declared as dtMyTable, I'm assuming I need to use dtMyTable.Select(), but I'm not sure if this is the best way.
The following VB line, where _DSversionInfo is a DataSet, returns no rows: _DSversionInfo.Tables("VersionInfo").Select("FileID=88") But inspection shows that the table contains rows with FileID's of 92, 93, 94, 90, 88, 89, 215, 216. The table columns are all of type string.
Further investigation showed that using the ID of 88, 215 and 216 will only return rows if the number is quoted. i.e. _DSversionInfo.Tables("VersionInfo").Select("FileID='88'") All other rows work regardless of whether the number is quoted or not. I understand that the numbers should be quoted just not why some work and others don't?
I am trying to select a row in a datatable using the datatable.select method as described in the help files. There are several examples and here is a typical one: Private Sub GetRowsByFilter() Dim t As DataTable t = DataSet1.Tables("Orders") ' Presuming the DataTable has a column named Date. Dim strExpr As String strExpr = "Date > '1/1/00'" Dim foundRows() As DataRow ' Use the Select method to find all rows matching the filter.foundRows = t.Select(strExpr) Dim i As Integer ' Print column 0 of each returned row. For i = 0 to foundRows.GetUpperBound(0) Console.WriteLine(foundRows(i)(0)) Next i End Sub The intellisense comes up with an error on the 'select' line: "value of type '1-dimensional array of system.data.datarow' cannot be converted to 'system.data.datarow'
I have the following piece of code that I am using to try and rip a csv file and turn it into a datatable. My problem is that the debugger never makes it to the return statement. Everything is appending to the datatable correctly, so I know that part works. Any idea's on what I can do to trouble shoot this further. Also, if you know of a simpler way to turn a import a csv file to a datatable I'd be very interested in learning about it.[code]..
It say that the Object reference is not set to an instance of an object. What's weird though is that it works through the whole data table fine. Could it be that the while loop is not terminating at the end of the file?
I have a datatable and I apply a filter to the defaultview.rowfilter property of that datatable. If I then loop through the rows collection of the datatable, will I only be able to see those rows that the filter applies to, or will it loop through all the rows?
I am working on a project that takes an xml schema and xml data files and places them into a DataTable, the 2 files are generated from a working table that i have written to disk. I wish to load these 2 files into a DataTable. Here is What i have
vb.net Friend Function CreateTable(ByVal tableName As String) As Boolean Dim table As New DataTable(tableName) table.ReadXmlSchema(tableName & ".xsd")
this however produces the following error on line 3
System.ArgumentException was unhandled Message=DataTable 'get_item_list' does not match to any DataTable in source.
get_item_list is the parameter passed into this function (tableName)
I have a datagridview bound to a datatable setting its datasource property to the datatable. I would like to have a child form that contains a list of columns associated with the datatable that contains a checkbox that will allow the user to hide and show the columns ( I do not know the best control to use here) (I assume this is the easy part as All i need to do is loop through each of the datatable's columns to get the column name)
now I would like save these visible columns on some event like form_closing so that the next time the user opens the form up it will remember the settings
I came across a problem with using a BindingSource as my DataGridViews.DataSource. Whenever I applied a filter to a column in the BindingSource and the user makes changes that don't match the column filter the DataGridViewRows would automatically disappear. A similar thing would happen when applying a Sort to a column. If the user made any changes the DridGirdViewRows would automatically sort causing rows to be moved around. This was not ideal for my application and there isn't anyway to stop this from happening with the BindingSource.
To correct this issue I have to use subsets of data. I use a DataView to apply the filter and sort to the main DataTable, which creates the subset DataTable.The problem is when I use the DataView.ToTable method I loose the Primary Key and RowError information. So I have to reapply this information everytime the user filters or sorts the DataGridView.Is there a better way to get a subset DataTable?[code]...
I have a datatable that has a resource in one field and hours used in another, it looks like this -
Resource Hours Used Manager 1 Accountant 1 Field Staff 2 Accountant 3 Manager 4 Manager 1 Administrator 6 Field Staff 4 Manager 0.5 Administrator 1
What I want to do is be able to create a summary of the data table above that groups multiple occurrences of a resource and adds up the hours used for that resource, creating a summary that looks like this -
Resource Hours Used Manager 6.5 Accountant 4 Field Staff 6 Administrator 7
I'm trying to get value from Datatable after Select Method.Select Method should return only one record.
Dim y As DataTable = CType(HttpContext.Current.Session("tb"), DataTable) Dim products = y.[Select]("StnID" = "'" + stnID + "'") Dim size = DirectCast(Products(0)("Shape"), String)
if I replace products with y--(DirectCast(y.Rows(0)("Shape"), String), it works.(which is before Select method, so it's useless) products is datarow object and I can't seem to get the value same way as datatable.How do I get value from datarows?
I have pulled information from a database into a datatable (dtCustomerInfo) then I expanded on the columns by processing the data and I can display this in a datagridview without any problem. However, the data is in detail and I want to ultimately summarize by customer name.The code below has a commented sql statement that is the statement I ultimately want but it is not working. However, the idea is that I want to Select from one datatable into another but run aggregate sum on several columns so that I will get one record per customer showing totals for each column.So I broke it down to just pull all data possible into the second table.[code]I do know the grouping in the current select * statement does nothing but my issue is more that the columns do not show up.
I'm using vb.net 2010.I have a DataSet with a Table and data. MyDataSet1 which contains Table1 I want to create another table that is the same as the Table1 but without data, but it should have the columns, etc.
I am trying to add NewRow to the database by using datatable in dataset, but before I do that I want to make sure that row is not already there. I create new row for the datatable I am working with, fill it with information. I fill datatable with the row from database that has the same primary key as my NewRow by using tableadapter.fill method, but when I do that my NewRow that was never added to the datatable is filled with information from database(and not information that I assigned to it). I count rows in my datatable before I fill it and it's 0, so why is my NewRow affected by Fill command? (I am using VB.NET 2005 Framework 2.0)
I am working on a vb.net app for a handheld using Windows CE and I have a few columns of data loaded in a datatable from a text data file. Some of the records can have duplicate Account IDs so I cannot use a primary key. What I want to do is take an Account ID entered and filter on just those records. I need to loop through all records with this Account ID, make updates to any of them and then clear the filter.
how to set a filter on a column based on a given string such as an account number? And loop through these records? Can I modify the records at that time?