How To Fill A DataTable With A List(Of T) Or Convert A List(Of T) To A DataTable
Nov 26, 2009
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.
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) {
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 have list of columns in DataTable to be added in list view. I have specified to the listview of columns in the order to appear and Datas as well.[code]
I'm trying to populate a List with a column of a DataTable in order to later convert it to a AutoCompleteStringCollection later. Is there a neater way to do it than the "good old" For Each?
Is there a way to use myDataTable.Rows.CopyTo for this task?
i want to build a datatable where each cell has a list(of integer)
is there a way to force the table to add automatically a new empty list(of integer) in each cell every time a new row is created without adding this cell by cell ?
I have a Business Logic Layer that contains function that return datatables. I'm writing a function that will return just the records that begin with the string passed in. this is what I've come up with so far:
Public Function FetchBusinessAreas(ByVal area As String) As List(Of BusinessArea) Dim AreasList As New List(Of BusinessArea) Dim dt As DataTable
I am currently writing unit tests for an application near completion (before management looks at it and turns it inside out). I am testing the business layer and a method is set to return a datatable of all "GroupID"s, which are simply an integer to represent the group that a user belongs to.
I'm assuming the best way to assert on this unit test would be to assert that the correct groupIDs are being returned from a controlled test database. However, I'm not sure how to assert on a datatable. Is the only (and best) possible way to accomplish this to simply loop through the datatable until it's empty and add each value to an array of integers? How would one go about asserting on this test?
I'm am creating a "pop-up" CheckedListBox over a button on my DataGridView. The values in the list are going to be filtered based on the value in column 0 of the DataGridView.I have already pulled in a "master" DataTable with two columns: ACODE and MATRIX.I want to call the following function and return an array of strings that I can use to build this CheckedListBox with. The line between "For Each r" and "Next" generates a "Number of indices is less than the number of dimensions of the indexed array". The number of items is variable in the array so I can't predefined it. I know I'm going down the wrong path.
Function StudyGroupSamples(ByVal sampleType As String) As String() Dim thisArray() As String Dim theseRows() As DataRow
I am converting DataTables to a generic list and need a quick and easy way to implement a Find function. It seems I am going to have to use a Predicate. Upon further investigation, I still can't seem to re-create the functionality. Private Function ByKey(ByVal Instance As MyClass) As Boolean Return Instance.Key = "I NEED THIS COMPARISON TO BE DYNAMIC!" End Function
Dim Blah As MyClass = MyList.Find(AddressOf ByKey) But I have no way to pass in a key variable to this predicate to do the comparison, as I used to do with DataTable..Dim MyRow as DataRow = MyTable.Rows.Find(KeyVariable) How can I setup a predicate delegate function in VB.NET to accomplish this?
Do not recommend LINQ or lambdas because this is question is regarding .NET version 2.0.
I have a table with 2 rows named timeStamp and value. I know I can iterate through the rows and create points and add them to a list (new point(timeStamp,value), but is there a way to do it without iteration?
I 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.
I have a vb.net form to add, modify or delete the product list..i have a datagridview in which i m loading data from sql server datatable...now i have a text box which accepts code for the product..i want that when i press a key, all data starting with that key should be highlighted in datagridview.....
eg i have product codes A001 A002 A003 C001 D001,, etc..
Now i press A in text box...in datagridview all data with A should be highlighted
I am loading a series of JPG images into an image list then using that to fill a list view. My program is using ALOT of memory by doing this. What would be the easiest way to add the images but take up less memory/time?
I can't seem to get a DataTable filled.url...I'm using VB, Visual Studio 2010.I keep getting an error on this line: adapter.Fill(dt)The Microsoft Jet database engine could not find the object 'Book1.txt'.Make sure the object exists and that you spell its name and the path name correctly.The name of the file and the path should be perfectly fine, although i did change the code just a bit:[code]I read somewhere that you have to 'drag a data adapter object from the Toolbox onto a form or component'.I don't have a DataAdapter in my Toolbox.I did a right-click and selected 'Choose Items.It is nowhere on the .NET Framework Components.
i want to fill a Datatable with a Datareader row by row but get an exception because the reader's columns have a different order than the Datatable's columns.
Why and how does a Datatable loads itself with a Datareader correctly, even so it has a column collection with different order?
I need to calculate values for every row so i dont want to load the Datatable completely but row for row. It has 25 columns so i dont want to set it all manually.
There must be a chance to load/fill/add a new row from a datareader without having the same column order(reader.GetSchemaTable?).
Following is what i have but what doesnt work:
Using reader As System.Data.SqlClient.SqlDataReader = command.ExecuteReader 'next line works(configInfo.DataSource is a Datatable)but is inappropriate configInfo.DataSource.Load(reader)
I am using a SQL query to fill a datatable from 2 associated tables. The first table has Products and the second has associated addonpackages. When I loop through my Products I am able to get all of the addonpackages for the first product but after that the datatable is only getting populated with the last addonpackage for each product. ie:
product 1 - all 6 packages are added tp the datatable product 2 - only package 6 is added to the datatable product 3 - only package 6 is added to the datatable ...and so on
My query follows. Why I am getting all of the info for the first product but just the last item for all others. No matter which product I would query first, I get all of the associated data with it but only the last for all others.
SELECT Products.ProductNumber, Products.Name, Products.Mnemonic, AddOnPackages.PackageNumber, AddOnPackages.Name AS PackName, AddOnPackages.Mnemonic AS PackMnem FROM AddOnPackages RIGHT OUTER JOIN Products ON AddOnPackages.ProductNumber = Products.ProductNumber WHERE (Products.Name = @ProdName) ORDER BY Products.ProductNumber, AddOnPackages.PackageNumber
I fill a data table with 11 columns and 1 row. Columns/ User Pass Row / **User2054** 1234 I have a Label named lblUser and I want to put the value=User2054 from my Table(Collumn[0], Rows[0]). How I can fill it?
I would like the main form I am designing in VB.net to appear as quickly as possible. As a result I don't want to fill a datatable in the load event but instead fill it as soon as the form appears, in the background.Then when a user clicks the button a listbox can quickly be populated.
With this in mind I called a function to fill the datable from the _Shown event. The trouble is that the form freezes until the query executes, making the process pointless for my needs.
Does anyone know how to keep the form active while the datatable fills silently in the background?
I'm getting a set of data by a datareader and assigning to a string. Now I need to fill the datatable columns with the Query fields. The datatable is connected to a grid to display the filled data. query is : strSQL = "SELECT EmpCode,EmpID,EmpName FROM dbo.Employee" Datatable columns are EmpCode,EmpID,EmpName. I need to read the query and assigned to the columns of datatable and fill the table. Me.DtShifts.Tables("NonAllocated").Clear() Me.DtShifts.Tables("NonAllocated").Load(dr)
I'm trying to solve a problem regarding types of list. First of all I have a stored procedure in my DB which does a select of a single column and I try to proceed it in my app in VB. By making a method function I declared a DataTable that loads through the SqlCommand(with the CloseConnection behavior). After that I publicly declared a List(Of String) which needs to be populated with the rows/items from the stored procedure that is on the way. Below is my snippet of the code:
Dim dt As New DataTable() Try If conn.State = ConnectionState.Open Then
[Code]....
It's LPrefix = collection.Cast(Of String)() where I get an exception error telling me that I can't really convert it. The old fashion way is to iterate with for/for each loop but that's not what I want for best use of performance especially if the list will have thousands of rows from a single column. So basically, I want to insert those items from that DataTable to the List(Of String) without For/For Each loop.
Running on VisualStudio2010 Ultimate, .NET FrameWork 4.0.
I was wondering if there is a way to change the Fill command text of a datatable before issuing it.I need this because the table I am opening has over 15 thousand rows and it hangs for a while in the network when filling the table. So I would like to tell it what to SELECT instead of getting the whole table and then applying a filter.If there's a way of doing that without changing the fill command, it will also work for me.
I'm trying to create a Server/Client Sync scenario for my application using Sync Services for ADO.NET specifically the LocalCache custom tool which sets the whole thing up for me.My server DB has 5 Tables, all of which are being synchronized to the client application, which now has a SQL Server Compact DB with the same schema as the server DB. I have a dataset with some custom queries that I use to connect my app with the local database.So far so good.However in my application when I try to fill one of my tables with the table adapter on my form (the default "fill" method) it gives me the following exception:No mapping exists from DbType Object to a known SqlDbType.
However, if I continue and do the fill again, IT WORKS without a problem. Try Me.WTSUsersTableAdapter.Fill(Me.WTSMainDataSet.WTSUsers)
fill a NEW DataSet's DataTable with data from a DataGridView? I am generating a data report that uses that "new DataSet." I need to go from a DataGridView to a DataSet because i need the person to be able to perhaps edit the information before its inserted into the report. my process to generate the report is...
- fill datagridview with advanced join sql - allow user to edit datagrid if necessary - put datagrids modified information in new dataset - set report's databinding source to new dataset - generate report...
I have a SQL db that holds the records for my page. On my page I have a details view I want to populate with records from my db. I can populate the records just fine, I need to be able to populate in records based on a user selection from a drop box?To clarify, on my main page I have a drop down list with years (ie. 2011, 2010, 2009), and a drop down containing account codes (ie. six-digit numbers). Based on what the user chooses for the year (for example 2010) and the what they choose for the account code (for example 123456) I want to populate the details view (which is on a seperate page) with only those records from 2010 and with the account code 123456??
