Use A Parameters Value As The Property To Be Selected In A LINQ Query ?
Aug 23, 2010
I am using LINQ-to-Entities and here is my query
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.
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'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")
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
I am facing a big problem with simple linq query.. I am using EF 4.0..
I am trying to take all the records from a table using a linq query:
var result = context.tablename.select(x=>x);
This results in less rows than the normal sql query which is select * from tablename;
This table has more than 5 tables as child objects (foreign key relations: one to one and one to many etc)..
This result variable after executing that linq statement returns records with all child object values without doing a include statement.. I don't know is it a default behavior of EF 4.0 . I tried this statement in linqpad also..but there is no use... But interesting thing is if I do a join on the same table with another one table is working same is sql inner join and count is same..but I don't know why is it acting differently with that table only.. Is it doing inner joins with all child tables before returning the all records of that parent table?
So the BlogPostTags table only contains 2 fields, BlogPostID and TagID.
When i run the query above i get 3 results back. Same blogpost 3 times but with 1 tag in each. It should return 1 post with 3 tags. The problem lies in the Tags query above.
I have an MVC3 app that I just added new db model to. I have created the connection to the database and I'm able to drag some tables and stored procedures onto the design surface. I have one sproc, however, that is giving me the above error.
Below is the script for the sproc in question. I am new to this and don't know what I might be missing. Where do I set the udttypename property?
We're developing a business ASP.NET application. Is it better to pass an entire entity to a method or pass each property of this entity as parameters? What is the best practice?
Case 1. Pass Customer entity to a manager - InsertCustomer(Customer cust) Case 2. Pass each property as a parameter - InsertCustomer(string name, string address...etc)
I have a web app for our golf club. When I compute handicap index for each golfer, I have to select the most recent scores and then a subset of those scores depending on how many rounds of golf the golfer has played. All the scores are entered into a single SQL Express table called "Rounds". Verbally, this is what I'm trying to do:
1) select the twenty most recent golf scores (sort on date descending, "take(20)") [if less than 20 records, then select all available];
2) for this set of records, select the 10 lowest scores (or smaller number if golfer has less than 20 rounds);
3) compute the average round differential for the subset of records, etc. to calculate handicap index (this step is working ok...)
My current VB code has this LINQ query (which is flawed -- it selects the lowest handicap differential scores of ALL records for the filtered user):
[Code]....
How do I modify this query to accomplish items 1) & 2) above? It seems this should be simple, but my experience with queries is still limited.
Using the properties as defined in a class, how about can I put them into the ParamArray parameters argument of my function. The code as follows:
Public Class MyObject Public Property Prop1 as string Public Property Prop2 as integer Public Property Prop3 as Boolean Public Sub AddNewMyObject MsSQL_ExecuteNonQuery("StoredProc_AddNewMyObject", ________________?) End Sub End Class Protected Function MsSQL_ExecuteNonQuery(ByVal storedProc as string, ByVal ParamArray parameters as object()) 'Some Code here. End Function
I am working on LINQ. I am calling a SQL Stored Procedure with 2-3 parameters it's working fine. When i am going to call Stored Procedure with 8 to 9 parameters the auto generated column is not comming automatically. So i am unable to use LINQ with Stored Procedure with multiple parameters.
I am going to return an Object depending on the Class and Year params. I want to remove the where condition when the Class and Year parames are null or zero.
Operator '==' incompatible with operand types 'ProductType' and 'String' ProductType is my Enum, and String is my input type. I don't seem to be able to convert one to the other.
I have an insert that uses an object data source with out the direction property set and it works fine. I noticed the direction property though and wondered if I should use it.Should the direction property for the parameters of an object data source be used with a simple CRUD operations?
I am working on a website in asp.net mvc. I have to show a view where user put some search values like tags and titles to search. I want to use the same Index method for that. I have make my form to use formMehod.Get to send the parameters as querystring.
[HttpGet] public ActionResult Index(string title, string tags, int? page) { if (string.IsNullOrEmpty(title) return View(null); [code]...
I am trying to set up a page that has two behaviors. I'm seperating them by URL: One behavior is accessed via /some-controller/some-action, the other is via /some-controller/some-action?customize. It doesn't look like the Request.QueryString object contains anything, though, when I visit the second URL...I mean, the keys collection has one element in it, but it's null, not 'customize'. Anyone have any ideas about this or how to enable this. I'd like to avoid manually parsing the query string at all costs :).
I am new to MDX and Sql Server Analysis Service and I've searched this high and low and read a lot of articles, but cannot figure out how.I know this is tough after reading so many articles online, and thus I am only trying my slim chance of getting something helpful from here. I need to create a sales report and want to parameterize the region, so, I'd like to have something likeSELECT blah blahFROM [MySsasWarehouse]WHERE @regionThe @region may take values such as [USA].[Northeast].[New Hampshire], for example.How do I make this happen with MDX? I learned that I can doSELECT blah blahFROM [MySsasWarehouse]WHERE STRTOMEMBER('[USA].[Northeast].[New Hampshire]')But, I have no idea how to have something like STRTOMEMBER(@region)and to be able to pass values to that @region variable.
In the end I would like to create a SSRS report using this MDX query and pass different values to @region. Do NOT point me to articles about how to pass parameters to SSRS, because I know how to do it through the URL query string.My question is How to create parameters for MDX query per se, and I haven't been successful in attempting to do so.
I have an update command with variables, is there a way to see the query after the variables are set?To see the full query as it sends to the DB. (i know in Java hibernate you could add some log file)
