DataSource Controls :: LinqDataSource.Select Syntax?
Jan 14, 2010
Where can I find documentation on the syntax that is expected for LinqDataSource.Select? It seems to be different from what I would do with Linq inline in C# code. For example, concatenateing something in Linq I would normally just do this in the projection:
new { FullName = (person.FirstName + " " + person.LastName ) }
However, with a LinqDataSource the only way I've found to do this is like this:
new ( String.Concat(person.FirstName, " ", person.LastName) as FullName)
I literally spent hours trying to figure this out, and only succeeded when I found a blog where someone gave this verbatim as an example. So I still don't understand why the syntax is different, the braces versus parens, aliasing, Concat operators. Next time I do this I want a better understanding so I am not playing this guessing game. It's like being handed a compiler, and trying to write a program when you don't know what language the compiler compiles.1. Are there different "flavors" of Linq? Like a VB Linq, and C# Linq?2. If so, is the LinqDataSource using a VB flavor of Linq?3. Really, what is really important to me, where can I find documentation on this particular falvor of Linq that the LinqDataSource expects? The documentation for the LinqDataSource itself gives nothing more than extremely simplistic examples.
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Similar Messages:
Apr 14, 2010
I will declarate a attribute, but it gives me an error
This query works fine and returns 1 record from type int:
SELECT TOP 1 DataObjectVersionID
FROM tblDataObjectVersionPropertyValueText
WHERE PropValue like CAST('00010281' AS ntext)
ORDER BY DataObjectVersionID DESC
And when I will declarate a attribute/parameter it gives me an error:
DECLARE @dataObjectVersionId INT
SET @dataObjectVersionId = SELECT TOP 1 DataObjectVersionID
FROM tblDataObjectVersionPropertyValueText
WHERE PropValue like CAST('00010281' AS ntext)
ORDER BY DataObjectVersionID DESC
Error message:
Msg 156, Level 15, State 1, Line 2
Incorrect syntax near the keyword 'SELECT'.
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Jun 3, 2010
<
asp:LinqDataSource
ID="LinqDataSourceSM"
runat="server"
ContextTypeName="SalesIntranetSolution.DataClasses.salesIntranetDataClassesDataContext"
OrderBy="reportTo"
Select="new (reportTo)"
TableName="cubeSalesRepRollups">
</asp:LinqDataSource>
Does somebody know how I can modify this LinqDataSource to select distinct records only?
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Aug 5, 2010
I have set up Linq to sql. I now need to fill a formview with a select that does a join across a few tables. Have not been able to find any example or tuts that go beyond the simple select. Any suggestions? Can this even be done?
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Jan 1, 2010
I have a problem with my SQL statement that only needs to show future dates in the Gridview.I use vb, vs 2005.I want a DateTime Field(TEndDate) to act as a control field in that only future dates (WHERE TEndDate >= Now.Date.Date) should be returned.It asks for my paramaterized value when I'm building the query.I'm unsure about the source I should select for the query.(The options are: None/Control/Cookie/Form/Profile/Querystring/Session)I'm losing my mind with this!Here is my code:
[Code]....
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Apr 19, 2010
I get the following error on the e.Command.Parameters("@latestRowId").Value line. It was working, but now not and I'm not sure why? Conversion from type 'DBNull' to type 'Integer' is not valid.
[Code]....
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Jul 4, 2010
I am trying to use this code:
[Code]....
And i get this error:
Incorrect syntax near the keyword 'AS'. What i am trying to do is SELECT details of a job and also SELECT which region the job is in. I currently have this: [URL] But i need to change it so it shows the Job name, details and then the regions..
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Jun 11, 2010
Im trying to build a where clause in c# for a LinqDataSource, but I cant get it to work, heres my code
[Code]....
when I set category to 'Concerts' tyhe where clause is
'Category = Concerts'
this generates an error telling me there is no column called 'Concerts'. I assume I somehow have to enclose the search term in quotes, Ive tried single and double quotes, but nothing works.
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Nov 16, 2010
So I need to take the literal "SELECT....FROM Bay....WHERE Warehouse=1 and ((BAY LIKE '1.0%' or BAY LIKE '2.0%'))I have set up a linqdatasource on my asp page and I want to bind that to a gridview. Here is the start of the HTML:
<asp:LinqDataSource
ID="dsBays"
runat="server"
ContextTypeName="CartonInventory.CartonInventoryDataContext"
EnableUpdate="True"
[code]...
How do I add a parameter so that it includes the LIKE statement?
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Jun 1, 2010
I have installed MySQL and set up an ODBC driver to point to a database in MySQL. In ASP.NET I have defined a connection string to attach to this MySQL dtabase.
<asp:SqlDataSource
ID="SqlDataSource2"
runat="server"
ConnectionString="<%$
ConnectionStrings:MySQLConnectionString %>"
SelectCommand="SELECT
* FROM [categories]"
ProviderName="<%$
ConnectionStrings:MySQLConnectionString.ProviderName %>">
</asp:SqlDataSource>
However in ASP.NET connection wizard, although the tables are shown, no colums are shown and when I attempt to run the page which uses this datasource I get an error message about a syntax error near page 1 at 'Select * from [categories]'. how to use an ODBC (MySQL) datasource in ASP.NET?
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Jun 12, 2010
I'v been using SqlDataSource and ObjectDataSource for a while.I would like to know about LinqDataSource and EntityDataSource. Therefore I have 2 questions to ask.1) Why do we need to use those twos? 2) In which cirmustances (Requirements) developers are using LinqDataSource and EntityDataSource?
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Mar 12, 2010
i am an asp.net beginner, i am a windows application programmer and currently i am working on big project " Human Resources" and i need to allow the users to apply for jobs using a web page.in windows application, i can use the bindingsource to bind textboxes and comboboxes to the fields of an object from L2S.and to bind the datagrid also to the detailed data and the page will be for inserting issue only,i.e i don't need to bring the data of applicants and certificates from the database, i just need some lookup data like maritalstatusCombo and availableJobsList things to allow the user to choose from.how can i do this using linqdatasource.
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Mar 11, 2010
I use LinqDataSource and GridView.
I need an old value of field "PictureBig" in RowUpdating handler like this:
e.OldValues["PictureBig"]
To achieve this I use bound unvisible literal in edit item template...
<asp:Literal ID="ltBig" runat="server" Text='<%# Bind("PictureBig") %>' Visible="false" />
Is there any better ways of doing this?
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Mar 23, 2011
I am trying to program the where prameters for this in code behind in C#, and is there really no way to do more than one parameter? Or am I not understanding this correctly? It seems only the 2nd parameter gets executed, no matter which one is at begining. I debug and seems they both get executed fine, but my listview doesn't get filtered and instead only the 2nd paramter works. Look at my code:
Also, if I do myLinq.Where = "division ==1 and someotherInt = 2", it works fine, but if I do two different data types, it will throw error. Since I want to filter with two different data types, hwo do I do this?
Parameter pram1 = new Parameter();
pram1.Name = "division";
pram1.DbType = DbType.Int32;
[code]...
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Sep 4, 2010
I'm having a question about the LinqDataSource. Does anyone know if it's possible to perform multiple inserts with the LinqDataSource? Let's say for example that I have 2 tables.
Table A
AID = PK autoincrement Name AddressA FK AddressB FK
Table B
BID = PK autoincrementStreetNumberPostalCodeCountry
These tables are just examples to clarify my question. Let's say that I have a FormView with a LinqDataSource where the user can enter his name en a billing address (A) en delivery address (B). Now I would like to know if the LinqDataSource is able to insert 2 records in table B and use these ID's to insert them in table A together with the name?
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Jun 15, 2010
I need to retrieve data using a date as an input parameter. I created a WhereParameter and passed in a date value that I know to exist in the database, but no data is returned. Heres my code
[Code]....
Ive passed in '02/06/2010' as the date, in the database, the Startdate column has several values of '2010-06-02 13:08:50.503' so I guess its not being found because of the time part. Whats the best way to make sure that I retrieve the correct data ? Im not concerned about the time at all, I just need all rows for 02/06/2010.
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Nov 18, 2010
If I have a Linqdatasource that isn't connected to a a bound control on my page how do I use the data source to read data in the code behind. ie
var query = (from x in linqdatasource select x)
What I actually want to do is create a data array (myArray) within the code, read all of the data from the linqdatasource (selecting 1 field to form tableDataArray), then compare the two arrays and then write (insert) those into in myArray that are not already in the datasource to the datasource (ie execute an insert back on the datasource).
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Mar 16, 2010
I just started working with LinqDataSources and I was wondering how you retrieve values in a FormView DataBound Event.
With an ObjectDataSource I believe you can grab them like:
[Code]....
Is there a similar way to acheive this with a LinqDataSource?
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Aug 7, 2010
I have a gridview on a page and based on the row selected I need to fill out a form view (dynamic data enabled) from a linqdatasource. On gridview_sleectedindexchanged I create the linqdatasource and set it as the datasource for the formview. It displays nicely but clicking update returns a "Could not determine a MetaTable" error for the datasource mapped.
THe goal is to create a single page that allows users to select a row then get the appropriate data, create an updateable formview so further edits can be done. Do not want to scaffold.
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Nov 15, 2010
I have LinqDataSource ID="LinqDataSource1" with values - EnableDelete="True", EnableInsert="True" EnableUpdate="True" on my ascx page, furthermore GridView, button a few textboxes, where a fill new values, which I would like save in my database. After click on button I insert new value to the table throught in function stored in ascx.vb page. It is works, but I don't know, how I refresh GridView on ascx page. I tried
LinqDataSource1.DataBind()
GridView1.DataBind()
without any good result, I must refresh page manualy (F5).
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Oct 21, 2010
have detailsview
<asp:DetailsView
ID="dtlviewRecommendation" DataSourceID="LinqDataSourceRecommendation"
DataKeyNames="PK_TT_RecommendationsSysId">
[code]...
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Jul 28, 2010
[Code]....
i am using gridview control and a linqdatasource and its all working fine and i have added the functionlity of searchingBySubject and i added WhereParameters and than binding my gridview (see the code below) but somehow its not returning any rows and i see i have number of rows based on what i am searching.
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Apr 21, 2010
Is it possible to assign the SQLDataSource.Select results to the LinqDataSource results ?
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Feb 12, 2010
With the gridview I can create a template field to query across associations but I don't see how its possible to do that with the listview (?). I tried to create associations in the eval fields
(ie productId.Brand) where productId is in the Reviews table and is associated with the Products table - and Brand is a member of the Product table but it was no go?
[Code]....
<b>Title:</b> <%# Eval("Title") %>
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Jul 30, 2010
How can i retrieve the data in linqdatasource in code behind?i have a dynamic database design with column storing the datatype eg. text, int, date.i need to retrieve the value in order to populate the control and bind it.
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