is there a way to update a column for all rows in a collection using linq like sql does it
eg. UPDATE myTable SET myColumn='newValue'
Also weighing options as to whether there is better performance using linq to sql for this or straight sql to DB via table adapters etc.
I am using
public int deleteProduct(int ProductID, int rowid) {
// Create the Database object, using the default database service. The
// default database service is determined through configuration.
Database db = DatabaseFactory.CreateDatabase();
DataSet productsDataSet = new DataSet();
[Code] ....
The above code am using but throwing below error how to resolve
"Update requires a valid UpdateCommand when passed DataRow collection with modified rows."
All I am trying to do is query the database, then get the returned values, so that I can do some calculations. But, I don't understand how to get the values from the database row that is returned, so that I can assign it for usage.
I would like to do something where the logic goes: for the index of [1] (which is just column 1), multiply it by 2. For the index of [2] (which is just column 2), multiply it by 3.
Example below:
This does NOT work:
[Code]....
i want to update many rows with difference values inside table. i'm coding a timetable.
View 3 RepliesI have a table with 2905 rows. I want to update one column with 2905 values. The values are all different, and they are just stacked one to a line with a line break. One on top of the other like so:
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
NULL
http://www.cargoarrainger.com/page6.html
http://www.iceretail.com/resources/link-7953
NULL
NULL
How would I write this query? Do they have to all be separated by commas? What about NULLS?
update tblAdvanceLinkBanned set ReciprocalURL=?
want to know if linq to sql auto updated the id column of a class (table row object) after SubmitChanges is called inserting a new row to that table, that would be fantastic, would anyone be able to confirm this?
View 2 RepliesI have an ASP.NET app with lots of textboxes all over the page that need updating at various points through program execution.
These textboxes actually belong to a certain class, so for easy updating I thought I could create a Dictionary(Of string, object) and add the control.ID and the control to it and then for updating do something like this:
(in case of updating textbox.text):
[code]....
However the text property of the textbox does not actually get updated. I'm mainly trying to avoid having to manually do textbox.text = somestring for each one of my textboxes every time I have to update them.
[Code]....
In above query I want to have top 10 rows as well as count of all rows.
Imagine I have 3 classes (student has Marks which has subjects)
[Code]....
I got a List<Student> populated with all the student and nested collection of corresponding Marks and subjects.How do I, before binding this list to any grid, filter records to display only those students, who surely have appeared in subjects with name "X" and "Y"?I tried something like:
[Code]....
I'm constructing a query using linq, but I'm having trouble using a collection, i.e. where field in database = anything in the collection.
Below is an example of what I mean:
dim keywords as string ="test,test2,test3,cats,dogs,frogs"
Dim getKeywords = (From cp In myDataContext.pages
Where cp.pageKeywords = currentPageKeywords.Split(",")
The aim of the above code is to return all records where the "pageKeywords" field contains 1st keyword, or 2nd keyword, or 3rd keyword etc.
I saw post [URL] .... which is converting rows into column item,quantity ,price. I have one other image field .how can bind image in this program?
View 1 RepliesI have a gridview with 3 columns. In second column I want to display some text in 2 rows and then a gridview.
Here is my code:
[Code]....
The problem is my third row is displayed as a row under first column. How do I make it a separate column in my girdview. Not sure what is going wrong.
here my code-
List<ReservationSlotLimitDetailEntity> sorted = (from p in slotLimitCollection.OfType<ReservationSlotLimitDetailEntity>()
where p.DayOfTheWeek == dayOfTheWeek
select p).ToList<ReservationSlotLimitDetailEntity>();
I want to sort in such a way so that it will add on more temp column "DayName" based on condition such that if dayOfTheWeek==1 DayName=Monday and if dayOfTheWeek==2 DayName=Tuesday and so on.
I have a bunch of news articles and I want to select the most recent one using Linq to Sql. I have an MVC action method like so
[ChildActionOnly]
public ActionResult LatestNews()
{
var article = mhndb.NewsArticles.Single();
return PartialView("LatestNews", article);
}
I would like to know the syntax for selecting the most recent item in the NewsArticles collection using Linq.
I'm new to LINQ and have a problem with my query not showing me the Table Collection. I manually created my Cart class and specified the table attributes on each property (works fine for inserting records via LINQ see below). DataContext dc = new DataContext(Conn);
var q = (from c in dc.NOTABLES?? where ((c.UserID == userID)) orderby c.CreateDateTime Based on examples I would expect to see dc.Cart But I don't, so I tried to access it via dc.GetTable<Cart>() which at least gets me data but doesn't seem to convert the rows to my Cart object since this:
foreach (var cart in q) Log.Info("UserID: " + cart.UserID + " CartID: " + cart.ID.ToString());
blows up with a "Specified Cast is Not Valid" exception.
No Problem Inserting Also, I had no problem inserting data into the database:
DataContext dc = new DataContext(Conn);
Table<Cart> Carts = dc.GetTable<Cart>();
Cart aCart = new Cart();
aCart.UserID = userId;
aCart.Description = description;
aCart.CreateDateTime = System.DateTime.Now;
aCart.UpdateDateTime = System.DateTime.Now;
Carts.InsertOnSubmit(aCart);
Carts.Context.SubmitChanges();
Using VS2005, VB code behind,
I am extending the GridView control to include a custom pager for a custom paging scheme (only one page returned from the database at a time rather than all records). In my testing a discovered an issue - on my last page of data, the GridView's rows property always returns a collection of PageSize page, rather than the actual number of records on the page, with non-data fill records being empty rows.
For example, suppose I have 23 records in my database. Assuming a PageSize of 10, when I page to the last page of data the gridview it properly displays the last 3 recrods - but when I handle the GridView's CommandName="Select" event the GridView's Rows collection contains 10 records, the last seven of which are empty.
I set a break point in just before I call GridView.DataBind and verified that the DataTable used as the DataSource for the last page of data does in fact only contain the 3 expected records. But when I set a breakpoint on the Sub that handles the "Select" GridView command, the GridView.rows collection contains 10 records, the last 7 of which are empty.
This post[URL] and comments make note of the issue but the solution prescribed by the author does not seem to work.
Attached are some snippets of my extended GridView and the two methods from my page where I mentioned setting breakpoints above.
Snippets from my extended GrdiView
[Code]....
MyReport.aspx.vb:
[Code]....
I have a partial class extending my Entity Model. I'd like to write a method that returns a collection of types from my entity framework model. For example, I'd like to get all the states to populate a drop down list. So I've written a method called getallstates(), similar to the example below:
[Code]....
I tried returning a list of Objects, and a list of states to my calling method to be used to bind to a drop down list. However I get an error that:
Server Error in Application. Unable to cast object of type 'System.Data.Objects.ObjectQuery to type 'System.Collections.Generic.List`1[System.Object]'.
What should my return type be for this function?
I'm new to linq. here is the scenario i need to write query for.I have a "Candidate" table with a varchar property "Skill"I have the table OR-mapped with LINQ to SQL on dbml file. Now I want to write linq query that:Selects all Candidates that have skill containing any of the keywords from ("asp.net","php","java")
View 1 Repliesi want to build a datagrid bound to a datatable with several columns. One column has only a dropdownlist with the number of the rows in the datatable.
Here a samplescreenshot:
[URL]
I know how to bind the columns to a grid and its no problem to create such a dropdown list with the content for me, too. But i dont know how to sort the complete datatabl after changing one value of one dropdown listbox.
So, how can i resort the values of a datatable column based on a given value and the datarow id?
I want to update multiple rows of gridview (only price field. for that i have added textbox) on click of update button which is outside of gridview.I have done following way
<asp:LinkButton ID="lnkUpdate" CssClass="BlueButton" runat="server" OnClick="lnkUpdate_Click">Update</asp:LinkButton>
[Code]....
Up to this its working fine but when no textbox updated then no need to go in for loop so i am looking for confiramtion before updating rows please help me how to do that becausei am less aware with javascript. another problem is textbox value disappear when page index changed how i can retain that values.
I have been trying to design a form, which uses a view model that contains an object array. I want to set up this form so that when the submit button is clicked, all the members of the array are updated. Here is my code:
The class definition of the array element:
[Code]....
The problem is that when I clicked the submit button, none of the luSubject objects in the array Subjects got updated. But if I set up some initial values for the members of the luSubject objects, for instance, set the Name field to be "Maths" in the constructor of luSubject class, then it got displayed on the text box when the form page was loaded. This suggests that this form could display the data in the array, but cannot update it.
This is part of a larger problem which has plagued me for a while now (see "EntityCollection already initialized" error with entity as model in Asp.Net MVC? for the entire picture).
But I found a web site with someone who had faced a similar problem and apparently solved it for his needs [URL]. I tried it, but had to make some modifications to fit my code, and the helper methods supplied by a tutorial by Steven Sanderson (see previous post).
I'm very close it seems, but not quite:
UpdateModel(consultant, "Consultant");
if (vm.Programs != null) //Unnecessary? Can it even be null if it's initialized from the model?
for (int i = 0; i < vm.Programs.Count; i++)
{
Program formProgram = vm.Programs[i];
Program modelProgram = consultant.Programs.SingleOrDefault(x => x.Id == formProgram.Id);
if (modelProgram == null)
_repository.AddProgram(formProgram);
else
modelProgram = formProgram;
UpdateModel(modelProgram); //Doesn't work. The modelProgram object does get updated with the correct property values, but it isn't saved to the repository...
}
_repository.Save();
Although this follows the example on the site above, and the modelProgram does get updated with the changed properties, these values are not saved to the database on _repository.Save() on the Consultant object, even though the modelProgram object is a reference to a Program object on the Consultant... What am I doing wrong?
I am using the Entity Framework by the way, if it isn't clear.
(BTW, if anyone has any input on the previous question and the whole picture, that would be welcome too, it is still unresolved).
UPDATE: There was apparently a mistake in here: UpdateModel didn't actually do any updating, I had just referenced a different object (the one in the viewmodel) for the modelProgram, so of course it had the right property values. I still want ideas for how to achieve this though...
I have a table converted from Access and the identity keys were lost. Now I need to make the id column the identity column, but it already has a lot of null values, how do I auto generate integer values for the null rows? The row ids are incremented, so if there is a way to auto increment the ids
View 7 RepliesI have an update / insert statements. If the user selects the checkbox IsPrestigeFeatured, I want that row to be set to 1 and I want all other rows to be set to 0. E.g. so there is only one row which is "Is prestige Featured"
My update statement:
ALTER PROCEDURE dbo.Update_Property
@propertyId int,
@propertyTypeId int,
@Name ntext,
@Price int,
@DescriptionResultsExcerpt text,
@Description ntext,
@Characteristics ntext,
@IsRenovation int,
@IsCharacter int,
@IsPrestige int,
@IsHomepageFeatured int,
@IsPrestigeFeatured int,
@CityId int,
@DepartmentId int,
@CommuneId int
As
UPDATE Property
SET Name = @Name, PropertyTypeID = @propertyTypeId, Price = @Price,
DescriptionResultsExcerpt = @DescriptionResultsExcerpt,
Description = @Description, Characteristics = @Characteristics,
IsRenovation = @IsRenovation, IsCharacter = @IsCharacter,
IsPrestige = @IsPrestige, IsHomepageFeatured = @IsHomepageFeatured,
IsPrestigeFeatured = @IsPrestigeFeatured, CityId = @CityId,
DepartmentId = @DepartmentId, CommuneId = @CommuneId
FROM Property
WHERE (PropertyID = @PropertyID)
I have following two collections,1. CategoryList, 2. ItemList. I need to get the collection which contains the rows shown in below in "Expected Result List".could you please provide me the LINQ query on collections to get this resulted List?
[code]...