What is the impact of creating variables using:
Dim ds as New DataSet
ds = GetActualData()
where GetActualData() also creates a New DataSet and returns it? Does the original empty DataSet that was 'New'ed just get left in the Heap?
What if this kind of code was in many places? Would that affect the ASP.NET process and cause it to recycle sooner?
I added queries to my dataset via the designer. Is there a way to use variables in those queries?
View 1 RepliesI need to fill a datatable(in data set) row by row by providing the the data by variables in VB.Net. The variables assigns its value by loop.. so the datatable row should be filled row by row until the loop ends. There are three columns in the table. so the table should fill with different kind of datatype variables.
View 1 RepliesWhen the user clicks an "Edit" button on my form, I want a box to come up which allows the user to edit a DataTable in a strongly-typed DataSet. What's the best way to do this?
View 2 RepliesI have code running in the Datatable.ColumnChanging event in my dataset. This dataset underlies a form and conventional drag/drop controls are in place for data entry.when the event triggers and runs, I am running code in the form that checks the dataset.HasChanges property. It is showing False. But this is immediately after the ColumnChanging event has been triggered.Okay, I see by others posts and MSDN that .HasChanges will only be true after moving off the row with the changed column. I have also noted lots of discussion about the advanced binding property of DataSourceUpdate Mode, but that does not address this issue.I guess I can do this by checking the state of the row for the binding source. Just seems odd that the event behind the dataset can be triggered and that does not change the dataset.HasChanges property.
View 3 RepliesI have tried everything I can to get beyond this error which shows below as <<<<< error here. It is trying to fill a dataset from a data adapter. If I change the SELECT statement to just SELECT * FROM xTable I get the correct number of records in each table. But anytime I try with a more complex statement I get the error message shown below which indicates System.Data.Common.DbDataAdapter.Fill(DataSet dataSet. I've completely erased all data and entered a new set of test data so I know there is no problem with relationships. Each table has primary key which is foreign key in other table. IS there something wrong with the Imports section: Imports System
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i am trying to copy data from a standard Dataset to a Type Dataset (XSD) of same table structure. i want to use Automapper to do that one. So how can i do that using automapper?
View 1 RepliesI need to pick all data in my application from my database and use it in my form
my question : how to pick all data in my application then i use it
I have two Datagrids, One grid has all the customers garments on it with style number and contact length. The other grid has the users who have garment issued to them. the style number is in both grids. I need to loop through the users grid and say if the contract number is 1 from the first grid then the contract date on the second grid will be todays date + 365 days (year contract) I have looked at using a stored procedure and also a for each command but I am just getting stuck with it all. [Code]
View 1 RepliesI have a problem saving a dataset which contains rows that i have imported from another dataset. i can successfully view the imported rows in a gridview but i cannot commit the rows back to the database.
View 2 RepliesDoes the memory used in declaring variables are reclaimed by the OS when these variables go out of scope?Does the memory used be released by setting thier value to nothing? if not, then how can I force the garbage collector to run or excecute at a certain/desired time..How about in Windows Forms..How can we make sure that the memory used in initializing and showing forms be released if those forms were closed?
View 13 RepliesI have multiple datasets that I would like to combine into one. There is a common ID field that can be associated to each row. Calling Merge on the dataset will add additional rows to the dataset, but I would like to combine the additional columns. There are too many fields to do this in one query and therefore would make it unmanageable. Each individual query would be able to handle ordering to ensure the data is placed in the correct row.
For Example lets say I have two queries resulting in two datasets:
SELECT ID, colA, colB
SELECT colC, colD
The resulting dataset would look like
ID colA colB colC colD
1 a b c d
2 e f g h
ok, I've finally got my test database issues sorted out, however now I need to actually modify my existing report to add the two new fields from my test database. I have made a copy of the report so that I am not modifying the original. I have deleted the two old fields and now want to add my two new fields in there. In the Field explorer window, I see an object called "dataset1" and when I expand it, it is using a view that includes fields from the table that I added my two new fields to.
The problem I see here is that I have gone in and modified the view to include these two new fields in my test database - but again, they are not showing up as selectable fields here. I am just assuming that "dataset1" is somehow pointing to the live database again and that I need to change the datasource location.In my solution explorer, I see an object called "dataset1.xsd" but the properties of that do not tell me much about where it is actually pointing to...
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I want to access data using both the datasets.
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Try
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In my code i have dataset name ds and table named Info1,when i write ds after that how tablename is coming,its not possible? How to do that ?
i am looking to map a dataset of addresses on a map. basically, i want the users to type a street name in my town and be able to see the houses that have signed up already on that street. so a pinpoint should show up on the houses that came up on the dataset.
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I have some concern about designing Datasets. I was told that it would be good to have a dataset for each table for maintenance purpose. Because frequent change in database tables is expected, having one dataset including every tables would be pain to make the corresponding change in the application.
Q. is it good approach to have a dataset for each table ( I would end up having 30~40 datasets for each db table using Stored procedure) ?
I have a separate project for commonly used datasets. each project include "dataset project" as a reference, and use it by including needed dataset into Forms, classes, etc.
Q. Does this approach makes the whole system to be slower? If I have a set of datasets as a separate project, it would be beneficial, since It will be easier to make a change (I only need to make modification in one place)
it returns date, and value by date.
for ex:
01.01.2009 454
02.01.2009 785
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I am having difficulties with Filling a dataset. It seems to be automatically assigning a datatype to the column based off of the first field of data it finds in that column. The column sometimes contains an integer, but it may also contain letters and numbers. If the first field is an integer, it says the fields in the column that contain a letter are DBNull. I'd like for the entire dataset to be formatted as a string/text type since I do not know what the values will be that I'm importing 100% of the time. How do I tell the dataset to expect a certain datatype for all columns and rows i'm going to import?
View 19 RepliesI have a datagrid which is already bound to a dataset, I need to get this dataset,make changes on some data, then rebind the datagrid with the modified dataset.
here's my code
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I have a form that has 1 text box and has 2 queries that locate the data. One is by customer ID and the other is by customer last name. They both work but when the code works and the user enters a customer ID and the query locates it then enters a customer last name it also locates it. If the user enters the same customer id again the query seems to fail. This is why I'm sure I need to add some kind of code to reset the Dataset.
Here's the code in the load sub procedure:
EditBoxSearch.Focus()
' Start out clean.
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I have a dataset (WW1Dataset) with one data table(WW1).(database used in an access database) I'm trying to filter the dataset e.g a user wants to filter by a chosen surname (SurnameTextBox.text) so the datset is filtered to display only those records wherethe surname column in the dataset matches SurnameTextBox.text.
View 1 RepliesI created a SQL database using the migration tool.I am converting my access forms to VB.net (VS2008).I am wondering if I create a single dataset in studio to the database or do I create a dataset for each form (query)? I am trying to determine what the best solution is. Many of my forms have drop downs that are populated using queries from tables.
View 3 RepliesI use a dbDataAdapter to populate a DataTable from an unlinked oracle database.I have a dbDataAdapter that I want to insert rows into an SQL Server table using SQLCommandBuilder.I have been trying all day to update the DataTable that references the SQL Server table with the data from the Oracle DataTable so that I can insert the rows.
View 2 RepliesI actually came from VB6 and starting to learn VB.NET. I saw this line of code which I cannot understand how it works nor how it goes.
Private MAX_VALUE As Integer = (1 << 14)
I have just been experimenting with nesting classes within a User class I had already created.
E.g.
Friend Class User
[Number of Properties...]
Friend Class Address
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I get the same error message!!! "Declaration expected". Also I notice the variable's name is not coming up in intellisense. I have not come across this before as declaring an using variables and objects has been straight forward up until now.
The user clicks a button, a new form is generated where the user enters his/her password? How can I keep an in-memory copy of the username?
For instance in web forms, I can just use Session ("User"). How can I replicate this with winforms?
I've created a 30 point wizard. Every step gathers between 1 and 3 variables. I've created a module and publicly declared the variables there. At the end of the wizard, one master form opens, gets all the variables, and displays them on one form. At this point calculations are run too which populates more variables. This works fine for one instance of the process.
the user may want to be running two instances of the wizard at once. Obviously, if the previous wizard is part complete and they start a new one, the variables are going to get crossed or replaced by the new wizard.Is there a way for the variables to be declared publicly but used in multiple instances?
OK, I'm working on a project and i need to access the property of a usercontrol which I have set.Here is the code in the UserControl
Private Color As Color = ColorTranslator.FromHtml("#000000")
Public Property InkColor() As Color
Get
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What's the proper way to declare variables in a class? I've been doing something like:
'in a class
public shared teststring As String = "first"
'on a code behind
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with shared variables loading a second window or reloading the page (without clicking the button) renders the hello world string. so how do I declare variables in a class but make it per instance?
When I am writing a sub or function that does some calculations etc. I often need a loop or a integer variable to count.
An example:
''' <summary>
''' Compare elements with the new data and perform all necessary actions.
''' </summary>
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As you can see, variables like timespan, nullCount and seconds are declared within this sub.
My question is, is it better to declare these in the class? I can imagine that would boost performance.