Why does the first method below work? I would have thought that the variable 'row' is completely separate from anything else, such as a row in DataTable1. Also, is there a drawback to using the first method? For changes to lots of columns in a single row, I'd rather do it that way.
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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 a form in my application that presents users with a datagridview which pulls data from database-a. I then offer the users the ability to edit that data but what I'd like to do is when they click the save event, that it saves their changes to database-b.
View 2 RepliesSo this doesn't seem like it should be that difficult, but apparently I'm overlooking something..? I have a datatable that has 4 columns. I want to output only the second column from the datatable. Here's what I've got so far:
Dim dt As New DataTable
** Datatable is set here **
Dim row As DataRow[code]....
I have a string array (values) whose elements look like this
1xxx:val:timestamp
1xx1:val:timestamp
and so on....
and a datatable that contains all the valid ids (the 1xxx numbers) and their corresponding names. I need to check whether or not the table contains the id and if it does i need to get its name.
This is my current code
Dim tbl as DataTable = GetTable("Select ......")
tbl.PrimaryKey = New DataColumn() {tbl.Columns("sensor_id")
For each value as string in values
[Code]....
but it seems like it is a round about way since I already know the element exists in the table and the select statement returns an array which i dont need because I know there will only be one datarow associated with this id. I feel like there should be an easier or actually more efficient way of doing this. If not oh well but I had to check anyway.
but this returns an array of datarows when i know I am only going to get one datarow from this query
I have a table with many values inside of it that might have single quotes around them. I need to create a duplicate table without those single quotes. I can't modify the original table as I need to use it, 'as-is' later.
I've done this with a table.Clone and using a foreach to loop through the rows and columns removing single quotes as I need and then putting that new row into the new table. It works and it's straight forward.....but
I'd like to do the same thing using LINQ. This was my attempt....
Dim myResults = From myRow In dtTable _
From myItem In myRow.ItemArray _
Where TypeOf myItem Is String AndAlso _
myItem.ToString.StartsWith("'"c) AndAlso _
myItem.ToString.EndsWith("'"c)
I had trouble finding examples that weren't looking at a specific column in the DataRow. It looks like my code does pull back all the matching results - but I'm at a lose for how I can create a duplicate table/modify the values?
The only requirement is to not using a For Each; as I already know how to do that. I've gotten closer - but I still can't seem to create a new row or a new table.
My new approach hits a dead-end when I try to do this:
Dim MyNewRow As New Data.DataRow With {.ItemArray = myRemovedQuotes.ToArray}
The Error message I get says, "Error 1'System.Data.DataRow.Protected Friend Sub New(builder As System.Data.DataRowBuilder)' is not accessible in this context because it is 'Protected Friend'."
Using VB.NET, what is the most concise way to convert a single column of a DataTable to a CSV? The values are integers, so I don't need to worry about character escaping or encoding.
View 1 RepliesI have a data table a simplified version of which is represented below:
Number | Group | Date | Client | Amount
--------+-------+-------+--------------+--------
1 | 220 | 28/12 | Company A | 0.345
--------+-------+-------+--------------+--------
2 | 220 | 29/12 | Company B | 0.451
--------+-------+-------+--------------+--------
3 | 240 | 26/12 | Company A | 0.510
--------+-------+-------+--------------+--------
4 | 240 | 27/12 | Company A | 0.510
--------+-------+-------+--------------+--------
5 | 220 | 30/12 | Company C | 0.151
etc.
I have a default view which represents the whole table.
But I need also a different view which represents the summary of the same data.
Code | Amount
------+--------
220 | 0.947
------+--------
240 | 1.02
In other words, I need grouped totals.
The question is - is it possible to accomplish by preparing a dataview for the datatable and assign it to the .DefaultView property (I need a user to be able to switch between detailed and summary views). Normally I always prepare views in a database but now I need to do it with DataTable and I simply have no experience of working with DataView class.
I have this working for a single field in a text but im trying to add more than one fields data .[code]...
View 7 RepliesI have a string like "Hello'World" and a Data Table with some records in it. One of those records is "Hello'World".he problem is, when I do a .Select in the Data Table, it only tries to search for the "Hello" part and throws an error on "World" because it interprets the ' (single. cuote) like the closing cuote on sql.DataTable.select("text = 'Hello'World'")I have gone through msdn doc, and it says I can escape some characters with [] brackets or f.slashes , but I just can't figure out: .select("text = 'Hello[']world'")
View 1 RepliesSay I have a code with 3 methods that do some pretty intensive work. Would executing these methods on 3 seperate threads be faster then executing them one after the other on a single core cpu? And what if it's a dual core or HT?
View 8 RepliesI am trying to make a list, separated by a comma, of entries from a single column in a SQL database. I have been spending the last several days searching for a way to do this, but every thing I found either didn't work, or wasn't exactly what I was looking for.
The query will pull all the email address that are not null. What I need to know is how to take the result of that query and make it look like this:
email0@address.com, email1@address.com, email2@address.com, etc, etc, ...
I feel like I should know this, but for the life of me, I can't remember nor can I find it in any of the textbooks I have.
I am using Visual Basic 2010 and SQL Server 2005. I also have access to Visual Basic 2005 if needed.
I use SqlParameters when executing database statements. I know that I can replace a single quote with two single quotes... but in the past SqlParameters took care of this for me. I have two projects.. in one, the SqlParameter does this and it handles single quotes fine, in another, it does not and I'm at a loss why (I even copied and pasted the code):
[Code]...
I am trying to use the DGV to view various properties from a variety of different class instances. Is it possible to bind each cell individually?
View 9 RepliesI am trying to update a row or a single cell in ms access through vb.net. But when i update the text box named NRIC, say for example i want to update "s4522147B" to "tr4521856C" and mean while leaving the other fields the same.
But the thing is when i make the changes in nric.text (textbox), the dataset actually updates the whole column in the table instead of the selected textbox.
Below is my code for the update part
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I am trying to display value of the field ("UserID") for every row exists in datatable to checkboxlist(make the checkboxlist item selected).
I used for loop, but only the field value from last row of RoleUsers table is selected in the checkboxlist.
Here is my code
Private Sub DisplayRoleUser()
Dim conn As SqlConnection
Dim cmd As SqlCommand
[Code].....
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?
View 6 RepliesI 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")
[code]....
this however produces the following error on line 3
Quote:
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 am currently working with a vb2010 front end with access as the database. everything works for accessing the information adding information. But when I try to edit/update the contents of a row I find that the update is being applied to the first row of the table rather than the target row. i have tried using the ID as a way to specify the row i want updated but that doesn't appear to work.
UPDATE ExamContent
SET Question = ?, ExamsText = ?, [Answer 1] = ?, [Answer 2] = ?, [Answer 3] = ?, [Answer 4] = ?, CORRECT = ?, LastEditUser = ?, LastEditDate = ?
[code].....
I know there are several ways to publish updates but I would like to know the best way to do it. What I already have configured is a shard network folder which I intend to have the program update from there. What would the best way to publish updates to the folder be?
View 1 RepliesIn the following code, TextBox5 reports conditions while the mouse is moving over the form, and TextBox7 reports only when the mouse has STOPPED moving over the form. When I start the program, and move the mouse from outside the form, onto the form and don't stop the mouse, the coords continually update in TextBox5 as expected. When I then stop the mouse, TextBox5 clears and TextBox7 reports, "Mouse Hovering", also as expected. Then if I start moving the mouse again, TextBox7 clears, and TextBox5 starts displaying mouse coords again, as expected.
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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 have a few problems i need to solve. Firstly, I am looking for a piece of code i can use to display a picture from a bank of pictures. It will work on the basis of generating a random number and loading a picture that corresponds to that number.
i.e. Dim RandNumber As Integer
Dim RandClass As New Random
RandNumber = RandClass.next(1, 10)
If RandNumber = 1 Then
Picturebox1.image = picture1
[Code]...
Secondly, can I then use subsequent picture boxes to display pictures from the same bank of images, without displaying the same image? Finally, I then need to be able to click the picture or a button beneath the picture to select it as an answer to a question and then the whole process starts again.
Is there a simple way to assign a populated datatable's columns to another empty datatable? That is, I want to copy a datatable's structure only but not its data.
View 6 RepliesI'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.
View 1 RepliesI am getting array of selected datarows from a datatable.select.I use the commands below to get that array or datarows
Dim foundRows() As DataRow
strExpression =
Here is what I tried.I have looked at examples by MS but they all just write to the screen and I have no interest in that.
For Each rowWork In foundRows
dtWork.Rows.Add(rowWork)
Next[code]....
"LineOfBusiness = 'CPP'"
foundRows = modXchange.pdtWork.Select(strExpression)
Now, I want to place the rows from foundrows into an empty data table.I did what I thought was the obvious but that only returns a bunch of rows with no data
load the contents of a query from a dataTable Adapter into a datatable?
View 2 RepliesI 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)
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