how the Lambda expression work specially in case of parameters (in the above case a & b) ? What is the basic concept of parameters in Lambda expression ? Can we use the names of the variables defined outside of the query instead of a & b ? which elements a & b represent in the above case represent ? Can we pass parameters from outside in the query ? If we can pass parameters from outside query then how it will be done? If you give me any other example instead of the above query to understand the concept of parameter in Lambda expression.
I have the following LINQ query which works correctly:
[Code]....
The following query, however causes an error:
[Code]....
"Could not translate expression 'Table(t_f2f_event).Where(e => ((e.EVT_START_DATE > Invoke(value(System.Func`1[System.Nullable`1[System.DateTime]]))) && (e.EVT_START_DATE < Invoke(value(System.Func`1[System.Nullable`1[System.DateTime]])))))' into SQL and could not treat it as a local expression."
@{Html.RenderAction("Detail", "Help", new { pageName = "press" });} But instead i'd like to use a lambda expression to get away from the string bits. I tried using the following (which is the nearest approximation i could figure based on my limited knowledge of the engine):
@{Html.RenderAction<HelpController>(x => x.Detail("press"));} But i get the following error:
The non-generic method 'System.Web.Mvc.Html.ChildActionExtensions.RenderAction(System.Web.Mvc.HtmlHelper, string, string, System.Web.Routing.RouteValueDictionary)' cannot be used with type arguments
However, i'm reading in the Apress MVC 2.0 book that it is in fact declared as a method that takes type arguments. Am i missing an assembly reference, or has it not been included in the MVC 3.0 Preview 1 build?
I have two lists. lst contains ViewState Data i.e All the records of the gridview & second lstRank contains the list of integer(i.e ID) for only those records which are marked as checked (i.e Gridview contains a columns for checkbox). Now i want to update the lst bool status depending upon integer ID of lstRank. How it can be achieved by lambda expression
public void SomeFunction(string searchField) { var data = from a in dx.SomeTable where [code]...
Now if I had to use the value of the parameter "searchField" as the property to be selected in the where clause then how do I do it ?
i.e I want to assign the value of the parameter "searchField" to the property I am checking in the where clause.
So ... the value of "SomeProperty" in a.SomeProperty must be the value of "searchField". How to do this ?
PS : I dont want a.SomeProperty=searchField. What I want is "SomeProperty" itself to be replaced by the value of "searchField" and then , this has to be checked to see if its equal to 270.
I need to get two fields from a database table (retrieved using linq-to-sql), one field is a datetime (and is a fixed field) and the other is always a decimal, but the field can be different.
The table holds currency data which is processed twice a day and in different currencies so could have fields such as AM_USD, PM_USD, AM_EUR etc. And I need to get data such as a list of the date against PM_USD or the date against AM_EUR.
I would like to be able to call the data using a lambda expression for example (this is a stripped out example):
data = TableData.Select(x=>new {x.DateTimeAdded, x.[**field name as string**]});
I have been trying to write a function to do this, and am failing dismally.
I'm new to LINQ and EF and I seem to be having trouble working this out.
I have a many-to-many relationship between my Location and Region tables. When adding or editing a Location, my interface allows the user to check any number of related Regions. If they click OK, I need to add any new relationships that were checked, and delete any existing relationships that have been unchecked. My basic code is shown below.
However, this code doesn't work. Lower down, the line location.Regions.Contains(region) returns false even when the location already is related to the region. The issue appears to be because the region is from my populated listbox that was initialized earlier and is no longer part of the current EF context. But if I try and add it, I get an error that there is already a Region with that ID.
It seems like what I want to do is change this line to something like location.Regions.Contains((r) => r.RgnID == region.RgnID) so I'm only testing for a particular ID. But this gives me the error "Cannot convert lambda expression to type 'TrailCalendar.Region' because it is not a delegate type."
I don't understand this error but, either way, I'm not sure how I can test if the relationship already exists without reloading a bunch of data, which I'd like to avoid.
I am using autocomplete functionality found at http://www.devbridge.com/projects/autocomplete/jquery/. In addition to the text in the autocompelete text box, i would like to pass additional information, like selected states and highways. Following is the code I have. I am getting the text value in the textbox in the MVC action, but not the params. Can you please check what I am doing wrong.
var a = $('.exit-filters div.filters input#Exit').autocomplete2({ serviceUrl: $('.exit-filters input#exit-autocomplete-link').val(), minChars: 1, [code]....
What will be the equivalent GroupJoin lambda expression in LINQ when I do this.
Dim fruit_salad = (From fruits In _DataContext_Fruits _ Group Join fruitRipe In _DataContext_FruitRipe On fruitRipe.fID Equals fruits.fID Into Group From fruitty_lecious In Group.DefaultIfEmpty() _
I am using following pivot query but not getting result as single row getting as 4 rows.
One more problem i am unable to pass dates as parameters to storeprocedure something like this
select [@date] .
SELECT 'Forecasted' AS HeadCount, [8/1/2010], [8/8/2010], [8/15/2010], [8/22/2010] FROM (SELECT * FROM TblEmpCount) AS SourceTable PIVOT ( SUM(EmpCount) FOR StartDate IN ([8/1/2010], [8/8/2010], [8/15/2010], [8/22/2010]) ) AS PivotTable;
I am getting result as 4 rows but i want result in single row like this
here is my query which is not working properly. I have 5 fields in my table Company, Reseller, Item, Code, Price. How can i get minimum Price when i pass parameters for Code is dublication value
Company Reseller Item Code Price A A-1 I1 C1 20 B A-21 I2 C2 13 C A-B I1 C1 19
select Company,Reseller,Item,Code,Min(Price) from Table1 where code='C1' order by Code HOW CAN I GET THIS BELOW TYPE OF RESULT
Company Reseller Item Code Price A A-1 I1 C1 20 C A-B I1 C1 19
i have a new question: i read all the tutorials that i found but i cannot understand how to pass a result of a linq to entities result to the view so that i can display the results. My query is actually in the controller function ot the view, i would now loop the results and display them in the page. How?
1. I have a GridView on my page and it uses sqldatasource with parameterized query. What I want to do is, on page load (where nothing has been selected so no parameter supplied), I want it to query everything (something like SELECT * FROM [this_table]) but since my SelectCommand is something like
SELECT * FROM [this_table] WHERE [this_column] = @someParameters AND [that_column] = @someParameters.
Can I play around with default value to achieve something like that but how ? Now, when the page loads, it doesn't show anything (No Gridview).
2. On my page, I made something like (username, gender, address, and more) and one single search button. That means, no single control enable auto postback. What I am trying to accomplish is building dynamic query
(if username specifed -> SELECT * FROM [this_table] WHERE [username] LIKE @username).
If both username and gender are specified (SELECT * FROM [this_table] WHERE [username] LIKE @username AND [gender] = @gender) and you know the rest. How can I do this using GridView and SqlDataSource ? To my knowledge, I can only specify one SELECT statement in a sqldatasource.
I've build a linq query.But i want a random selection so its not always ID : 1,2,3,4,5,6 How can i randomize this var? I like to bind it to a repeater.//TagCloud:
Random rand = new Random(); var tc1 = from i in JumpTide.cms.menu.GetMenuItems(32) select new
here is my code for selectiong some records from db table
string strSql = "select * from mtblNBD where SentTo=@SentTo and InternalStatus Is NULL order by DeadLine desc"; SqlCommand com = new SqlCommand(strSql, con); com.Parameters.Add("@SentTo", SqlDbType.NVarChar, 50).Value = (string)Session["uname"];
here I am using parameters for SenTo field but not for NULL so it is ok... or should I use parameters for this field where value is NULL , if yes then how can I use parameter for this
