Linq Data Source - adding a where clause

Newby question related to LINQ and LINQ DataSource.

I have a standard ASP web page with a gridview attached to a linq data source.  A sort order is applied to the data so the most important data is generally at the top but sometimes I need to search (a very simple search)...

I have the code working by putting a hard coded string into .Where but I am confident that is NOT the best way to do this.

With User_Grid_LinqDataSource
   .Where = "First_Name.Contains(@SearchText) or Last_Name.Contains(@SearchText)"
   .WhereParameters.Clear()
   .WhereParameters.Add("SearchText", txtSearch.Text.Trim)
End With

The rest of the story...  I have 2 distinct searches based on a combo-box. 'Name' is shown above and 'Address' is the other one.

How do I use linq to apply different where clauses?

jongrossexAsked:
Who is Participating?
 
dexterrajeshCommented:
hi,

pl refer here for some quick samples: http://msdn.microsoft.com/en-us/library/bb397927.aspx
0
 
jongrossexAuthor Commented:

Thanks. My questions was NOT clear, my fault.

I understand how to create the LINQ query but I do not understand how to associate it back with the LinkDataSource so that it is reflected in the grid.

So after I do the query like below...

var queryLondonCustomers = from cust in customers
                           where cust.City == "London"
                           select cust;

How do I associate the results with the data source so that it will be displayed on the grid.  I assume it is simple but I can not find the answer... or is there a better way to think about this.

-Jon

0
Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

 
CodeCruiserCommented:
Try using the Where property of the LinqDataSource itself to do the filtering

http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.linqdatasource.where.aspx
0
 
jongrossexAuthor Commented:
We are getting closer...  but from the above link I do not want my query coded in a string.

The following code attaches linq data to a gridview

Dim db As New SjuDatalassesDataContext
Dim searchText As String = txtSearch.Text.Trim
Dim userList = From u In db.vUser Where u.First_Name.Contains(searchText) Select u
grid.DataSourceID = Nothing
grid.DataSource = userList
grid.DataBind()

How do I either
- tell the LinqDataSource 'control' to execute the query from the above Linq command
OR
- attached userlist to the LinqDataSource 'control'


0
 
dexterrajeshCommented:
hi

can you give a try to the select property of the linqdatasource control http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.linqdatasource.select.aspx

Linqdatasource control is meant to perform the linq operations..... hence it comes with all required properties and methods to perform linq operations... I am not sure why you want to deviate from this...
0
 
jongrossexAuthor Commented:

What I am trying to get away from is a string for the where clause
   .Where = "First_Name.Contains(@SearchText) or Last_Name.Contains(@SearchText)"

If my data model changes I do not find out till runtime

Does the 'linqdatasource' have a property that allows me to add a link command?  For example:
From u In db.vUser Where u.First_Name.Contains(searchText) Select u
I have looked and did not see any such functionality.

Thanks for your help
0
 
dexterrajeshCommented:
no you can't do that...
0
 
jongrossexAuthor Commented:
That seems exactly what I was looking for.  I will give it a try tomorrow.

Always enjoy Scott Gu's blogs.
0
 
CodeCruiserCommented:
Any Luck?
0
 
jongrossexAuthor Commented:
Sorry for the delay... that was perfect.
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.