How can I use dynamic fields in LINQ in the PART OF THE where query? I mean that I want to write where x = *dynamic fields* I want to do the select query in all of the tables that are in the dataset, not on one datatable.
View 1 RepliesI'm trying to query old Access database tables and compare them with SQL Server tables.They often don't have primary keys, or they have extra fields that had some purpose in the nineties, etc., or the new tables have new fields, etc.I need to find records - based on a set of fields specified at runtime - that are in one table but not another.So, I do this kind of query all the time in SQL, when I'm comparing data in different tables:
dim fields_i_care_about as string = "field1, field2, field3"
'This kind of thing gets set by a caller, can be any number of fields, depends on the
'table
dim s as string= ""
[code]....
It tells me it can't convert a Boolean - Is there any way to do this without Linq expressions? They seem far more complex than what I'm trying to do here, and they take a lot of code, and also I can't seem to find examples of Expressions where we're comparing two fields in a subquery.Is there a simpler way? I know I could do the usual EXISTS query using JOIN or IN - in this case I don't need the query to be super fast or anything. And I don't need to use a DataTable or DataSet - I can put the data in some other kind of object.
I would like to bind a DataGridView to a different LINQ query every time (in order to reuse the same form/DGV for different queries), like this:
[Code]....
but the "Qry", and the number of comboboxes, and their field names would change every time.
I need to represent the following query using LINQ:
DECLARE @PurchasedInventoryItemID Int = 2
DECLARE @PurchasedInventorySectionID Int = 0
DECLARE @PurchasedInventoryItem_PurchasingCategoryID Int = 3
DECLARE @PurchasedInventorySection_PurchasingCategoryID Int = 0
[code]....
Now, I know that a query in .NET doesnt look like this, this is my test in the SQL Design Studio. Naturally VB.NET variables will be used in place of the SQL local variables.My problem is this: All of the conditions after "WHERE" are optional. In that a query might be made that uses one, some, all, or none of the conditions. V.PropertyID and V.Value can also appear any number of times.In VB.NET I can make this query easy enough by simply concatenating strings, and using a loop to append the "V.PropertyID/V.Value" conditions.I can also make a Stored Procedure in MS SQL, which is easy enough.However, I want to accomplish this using LINQ.
Example-I have a person class
Public Class Person
Private _fname As String
Public Property Fname() As String
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Forgive my ignorance on this.I have this LINQ Query:Dim ngBikersDataContext As New CarBikeWalkDataContext
bikersList = (From c In ngBikersDataContext.Reg_Bikers _
Order By c.L_Name _
Select New Bikers() With { _
.BikerID = c.BikerID, _
.F_Name = c.F_Name, _
[Code]...
with the error "Overload resolution failed because no accesible 'Select' accepts this number of arguments."
Over the "NEW" I get an error " ')'expected."
I have a data grid view on a form which is currently filled with the following query:
SELECT TopicCode, TopicName, NoOfCourses, Lev FROM tblTopics WHERE TopicCode = @TopicCode1(Where I obviously pass a TopicCode parameter)
However, I have added two custom columns to the data grid view, and the values that i want be in here are in a different table than the query i'm using to fill the data grid view.is it possible to "nest" queries? which will allow me to select fields from two different tables?
Example:SELECT TopicCode, TopicName, NoOfCourses, Duration, Lev FROM tblTopics AND SELECT StartDate, EndDate FROM tblSubscriptions WHERE TopicCode = @TopicCode1
Possible? or not?
I have two forms receipt and payment. Both are having almost same fields.e.g. entryno, date , partyname, amount. Should I create two different tables for receipt and payment or keep data in single table with additional field 'TransactionType'
View 3 RepliesIs it possible to dynamically change the type of the object in a class?say, I have a Filter class, that specifies a filtering condition for a list of objects of a specific ObjType
Public Class PropertyFilter
Public Property ObjectType as MyObjectsTypeEnum
Public Property MainObjectProperty As ??? OBJECT
[code]......
Im not too sure if this is the correct place for this question, but I couldn't find anywhere else..Heres what i want to do. I have two tables in an Access DB. TableA and TableB. Each Table has only one column called Picture, and that column is filled with the names of pictures (picture1, picture2, picture3, etc)
Thing is, that The pictures in TableA have equivalent pictures in TableB. They are not named the same, but the pictures themselves are the same i.e.: TableA Picture1 = TableB Picture3, TableA Picture2 = TableB Picture5.
What i Would like to create is a form that has two datagrids, or Listboxes populated with the data from each table. One for TableA, One for TableB. When the User selects a picture from one of these controls, The other control must show which picture the selected one corresponds to (if i select TableA Picture1, TableB Picture3 becomes selected showing that they match)
I think that most of the work will be at the actual DB, somehow linking each and every field, maybe a one to one link between fields/cells in the DB, then in VB calling that one record that was clicked on, seeing what relation it has to the other table,
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Using Visual Basic 2008 express, I would like to access a database with 2 tables, one table (useraccounts) which has Users and Password and ID, and the other table which has information (linktable). Basically I would like to do a login form which reads from the table useraccounts and be able to create new users which will write into the database.
Another is that I have a form with a number of links which I would like to store in the table 'linktable' and it basically just gets the links from the table and straight to the form where it is used. I have tried using access or the .mdf files that visual basic has but I have been unable to find an answer for either.
I wouldn't mind using either access or the .mdf file for the database, I would just like it to work. Overall I am trying to get:
Login form which reads from database table 'useraccounts' and has a new user feature
Just a form that can read / write to the database once the save button is clicked.
I've got a DetailsView which has some static fields defined in my markup and adds some extra fields dynamically in the VB codebehind. It should be noted that the DetailsView lives in an UpdatePanel.Assume that I would like to get inventory information for a number of warehouses, but I only want to see those which have stock on hand. In addition I have some static information such as product, sku, etc.
The problem I was having was that every time I clicked the "Details" button it would just keep appending the dynamic fields to the end and never re-rendering the table. I figure I either need a conditional or to tell it to re-render somehow. I suspect this problem arises from my use of the UpdatePanel but it's important for the user experience of my customer to keep this.
'Warehouse Stock by Location
Dim stockDT As New DataTable
For Each row As DataRow In stockDT.Rows 'Add column for each Warehouse that has stock
[code]....
I have VS 2008 and am working in VB.Net forms.I have a webbrowser control where I am trying to control input fields that are dynamically created. If a text field has proper handles such as id and name tags there aren't any problems.For example, I am trying to work with twitter for posts. I know twitter has an API but I want to work with many similar systems and want to avoid the API as its case specific and I want to scale things within the VB.Net form. The login fields for twitter are easily handled, however
the posting field once your logged in is just a text area with a class. There is a tagname but I have been unable to post using the tagname element.
[Code]...
I'm looking for a way to combine a field from multiple tables into a single field in a new table. Because the data populating the tables is coming from an outside source, I would prefer not to change the data in the original files. I have a separate table for each year because this is the way the data is provided. The field layout is not consistent from year to year, but each year there is a field that we'll call "score." I'd like to pull the field "score" from each year's table and have it populate a "score" column in a new table along with the year of the data so that all the years' scores are in the same place. Is there a way to do this using Visual Basic + Access?
View 3 RepliesI have VS 2008 and am working in VB.Net forms.I have a webbrowser control where I am trying to control input fields that are dynamically created. If a text field has proper handles such as id and name tags there aren't any problems.
For example, I am trying to work with twitter for posts. I know twitter has an API but I want to work with many similar systems and want to avoid the API as its case specific and I want to scale things within the VB.Net form. The login fields for twitter are easily handled, however the posting field once your logged in is just a text area with a class. There is a tagname but I have been unable to post using the tagname element.Any examples of posting to twitter without the API ?
web1.Document.GetElementById ... ?
web1.Document.GetElementsByTagName ... ?
I've done extensive searching but can find nothing to make it happen. DOM inspectors havn't revealed much about the field.
I use Visual Basic 2010 Express. I want to create a WinForm app in which there are several buttons "table1", "table2"... Each button must display the corresponding table of a database in a specified region of the same form.
I'm able to link a MS Access database (.accdb) file to the app. But, how do I create that dynamic area whose content would be one of the database tables of the linked database? I tried using DataGridView, but I'm a newbie and I'm missing something; it doesn't work.
I have Joined two tables into a datagridview and i want users to be able to update the table values but i have this error,which is the title of this thread.Is there any alternatives of updating a joined table in datagrid view? here are my codes
Private Sub Search_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
con.Close()
Dim cmd1 As OleDbCommand = New OleDbCommand("SELECT LECT_NAME,LECT_ADDRESS,LECT_CONTACT,SUB_SEMESTER,SUB_ID,SUB_NAME FROM
[code]....
I have a table in my database that the fields of it are not fixed in number and name. in fact this table is the statistical report of other sections of my database.I want show this table in a data Grid View after finish calculation. I created a dataset and connected it to my Data Grid but the number of columns and names of them are not flexible and don't change according new statistical reports that would be available in my table.Is there any way to update my dataset and recreate it according to my new information in my table and show it correctly with Data Grid?
View 1 RepliesI'm trying to concatenate two fields in LINQ so that I can then filter with a keyword. I found a question posted here that I thought was my answer, but I'm getting 0 records back for some reason. This is supposed to return a JSON result for an autocomplete textbox (it works when I don't concatenate fields).
Here's my code:
[Code]...
i need to create sql tables based on user needs lets say a guy needs a table of 4 rows 5 columns other user needs 3 rows 3 columns each with different types so how is the best way for letting them choose like they write in a text box ( this will be the value of rows)4 and another text bvox the count of columns and i have those 2( rows and columns needed) numbers i create the table as is.based on those. by default i create type as varchar max then later on we must fill the table using datagrid.
View 14 RepliesI apologize if it is not. I am trying to write a script in Visual Studio 2008 (using a VB project) that will, upon the clicking of a button:
- A file object will be created.
-Said file object will read in a number of files from a specified file path.
-A dataset will be created and populated with fields from two columns within a database table; app_id and company_name.
-The script will read through the file names and fields recorded in the dataset, renaming the file to the app_id if the original file name contained the company_name.
The code I have so far to do this:
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
'Create the file object
Dim objFSO
The problem is that currently this code will only rename the file if the file name and company_name match exactly, ideally I'd need to include a clause to make it rename if the file name is "LIKE" or "contains" the company_name.
I have a Table:
[Code]...
I'm trying by LINQ-query (VB.NET) to return a count for distinct value of Objects, Stuffs and Colours for every Room:
[Code]...
I am stumped. I have a DTO object with duplicates patient address data. I need to get only the unique addresses.
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I have a dynamic query which returns a DataTable. This DataTable will contain a varying number of columns depending on the selection used in the query. I want an efficient way of filtering the records in the DataTable.
For Example The DataTable contains columns : A, B, C and D
I need to query this data at serveral points in my program. At some point I may need records where A=10 and C>40. At another point I may need records where A<10 and D=90 etc.etc. The selects are dymanmic, I do not now what Columns or values are needed until the code is executing.
I could simply use a DataTable Filter and build the selection string dynamically. I have no problem with this. However I was wondering if using LINQ would be more applicable. I am completely new to LINQ and would like to use it but don't know its capabilities.
(At present I am using a DataTable but in future this may change to a collection of Objects)
Please anybody help about how to create two dynamic combo box. Like Country and province.. when I select country conutry Combo box then Province Combo box automatically show same country province.[code]
View 5 RepliesHow would I get something like this to work so that I can dynamically alter the where-clause in this linq to sql query?
Dim AccountID = 1234
Dim AccountList
Select Case Types
[Code]....
With the above code I get this error:
Late binding operations cannot be converted to an expression tree
I have a typed dataset with 2 tables and a relation between the 2 tables. The relation is a 1 to 1 relation.First, who cane help me how to bind both the fields of the parent and the child table to a textbox.And second, in the dataset designer you cane preview the data. There a see for each record 1 row with all fields of the parent and also the fields of the child table. How cane i have the same result in a datagridview?
View 1 RepliesThe LINQ VB code below is to read the first record data for database table
ProductTable that has 3 colounms (or 3 fields):
TableCol1, TableCol2, TableCol3. The reading data is stored at variable
MyArrayFirstRow.
'-------start LINQ VB code in Visual Studio Web Developer 2008-------'
Dim MyArrayFirstRow
[Code].....
My LINQ query contains the following Group By statement:
Group p By Key = New With { _
.Latitude = p.Address.GeoLocations.FirstOrDefault(Function(g) New String() {"ADDRESS", "POINT"}.Contains(g.Granularity)).Latitude, _
.Longitude = p.Address.GeoLocations.FirstOrDefault(Function(g) New String() {"ADDRESS", "POINT"}.Contains(g.Granularity)).Longitude}
The query works, but here is the SQL that the clause above produces
SELECT [t6].[Latitude]
FROM (
SELECT TOP (1) [t5].[Latitude]
[Code]....
but this produced an error: "A group by expression can only contain non-constant scalars that are comparable by the server."
I have one dataset with two tables and when some values from tables are changing I need somehow to change the values from table 2. Table one is conected to an SQL server. One table 1 receives a message from sql service broker it automatically reload all the information. I need in that moment to compare what I have new in table 1 and put it in table 2. I have made with <br />For i=1 to ..<br /> </p>
View 6 Replies