C# - The Type Arguments For Method System.Linq.Enumerable.OrderBy Cannot Be Inferred From The Usage
Jan 28, 2011
I'm trying to follow the demo from this link to add a jqGrid to an MVC app.
I have a table named Companies that I'm trying to display in a grid. A Company simply contains an ID and a Name.
I'm running into an error in my controller function:
public JsonResult DynamicGridData(string sortIndex, string sortOrder, int page, int rows)
{
int pageIndex = Convert.ToInt32(page) - 1;
int pageSize = rows;
var companies = companiesRepository.Companies.OrderBy(sortIndex + " " + sortOrder).Skip(pageIndex * pageSize).Take(pageSize);
//Error here
...
}
I'm getting an error on the line that is calling OrderBy():
The type arguments for method 'System.Linq.Enumerable.OrderBy(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly.
I really have no idea what the error means, and I haven't been able to find an explanation. I'm not sure what is causing this error on a simple OrderBy function.
I have a table "OSTAN" with two columns "ID" (Key index) and "NAME". I am trying to construct a linq query to select the Name for a specific ID. I have not luck trying to construct the where clause. Here what I have so far:
using (XeledsEntities db = new XeledsEntities()) { string SelectedName = db.Ostans.Name.Where( Ostan=> Ostan.Equals(Request.QueryString["Ostan"])).FirstOrDefault(); }
Can anybody construct this where clause to set the Selected Name?
I am creating an Asp.net web site which will support dynamic data. When I am creating a dynamic web site from Scratch (from template in VS) all is working fine. But when I am trying to add dynamic entity (.edmx) file and running the application I am getting following error
"The method 'Skip' is only supported for sorted input in LINQ to Entities. The method 'OrderBy' must be called before the method 'Skip'. "
However, when I try to build the control I'm getting the error as shown in the subject. I've tried searching, and it seems the signature for the original function matches the one I have, and all other solutions I've seen uses the same signature.
The following code works fine for converting an XML data set to be enumerable for Linq.
'Query webservice for data Dim propertyInfo As String = myService.GetProperty(userName, password, Acct) ' Create a new DataSet.
[code]...
However, it does not retain the xml tags in the Linq enumerablerable dataset ('newDataSet2"). I don't think I can rely on the array index order as being the same everytime, so this would obviously cause a problem if I'm trying to align the array items up to my database fields. How can I make newDataSet2 retain the XML tags (column headings) to insure I know what data field each array item belongs to?
Now I know there is a reason to this odering but my tiny little brain can't get my head around it.I am using a webservice to pull through data to a webp[age and have the following that is so far pulling data through from UUF1:
I'm playing with an EntityDataSource and specifying a simple order by clause containing one column name, for instance "it.[DNS_NAME]".
When I run the following:
[Code]....
I get an EntitySqlException saying that @sort's type is incorrect. It is expecting a Transient.rowtype that matches one of the columns. What is going on here? Order by parameters don't really have a meaningful type other than a string in my opinion. When I try specifying DbType.String instead of TypeCode.String, the same error is thrown.
The exception:
'@sort' is not a member of type 'Transient.rowtype[(SOFTWARE_DSPL_ID,Edm.Int32(Nullable=True,DefaultValue=)),(COMPUTER_NAME,Edm.String(Nullable=True,DefaultValue=,MaxLength=64,Unicode=True,FixedLength=False)),(DNS_NAME,Edm.String(Nullable=True,DefaultValue=,MaxLength=64,Unicode=True,FixedLength=False)),(DIRECTORATE_NAME,Edm.String(Nullable=True,DefaultValue=,MaxLength=24,Unicode=True,FixedLength=False)),(OS_BROAD_CAT_NAM,Edm.String(Nullable=True,DefaultValue=,MaxLength=25,Unicode=True,FixedLength=False)),(OS,Edm.String(Nullable=True,DefaultValue=,MaxLength=64,Unicode=True,FixedLength=False)),(EQP_TYPE,Edm.String(Nullable=True,DefaultValue=,MaxLength=64,Unicode=True,FixedLength=False)),(EQP_PROP_NO,Edm.String(Nullable=True,DefaultValue=,MaxLength=10,Unicode=True,FixedLength=False))]' in the currently loaded schemas.
How can I dynamically provide the column name to order by?
Is there a way to use the OrderBy command in Linq with a DateTime field using the Date portion only (without the Time Stamp portion) that is nullable such as in the following query?
var query1 = from myTable in MyTable where myTable.EnteredDate != null group myTable by myTable.EnteredDate into myOutput[code]....
Since myTable.EnteredDate is a DateTime field that can contain nulls, it does not support the .Date conversion call such as myTable.EnteredDate.Date
Is there a way to convert the myTable.EnteredDate field into a date only string in the group by portion?
If I have below code, how to make it work as it has below compile error:
Error: cannot implicitly convert type 'System.Linq.Iqueryable<system.data.DataSet> to 'System.Data.Dateset'. An explicit conversion exists.
public DataSet GetProductList() { using (var sdatabase = new DatabaseDataContext()) { IQueryable<DataSet> result = wmsdatabase.ExecuteQuery<DataSet>(@"SELECT productid, productname from product group by productid, productname").AsQueryable(); return result; // Compile error here } }
I understood that we can use System.Type.InvokeMember() to invoke method dynamically using Reflection, but I couldn't get proper example to show how to work on it. Can anyone please explain how to do it in Visual Studio 2010
Just for practice purpose I have created one class called MathFunctions like below: namespaceCSHWEB { public class MathFunctions { public double SimpleInterest(double PrinicipalAmount, double TimePeriod, double RateOfInterest) { return (PrinicipalAmount * TimePeriod * RateOfInterest) / 100.0; } } }
Now, how can I invoke above method SimpleInterest with its parameters without instantiating the class?
I wanted to delete the record from data but I receive this error "Unable to cast object of type 'System.Data.Linq.DataQuery`1[training_eval.Course]' to type 'training_eval.Course'.
Dim eval_sure = From ev In db.Evaluates Where ev.course_id = indexcourse Select ev.course_id Dim del_course = From c In db.Courses Where c.Course_id = indexcourse db.Courses.DeleteOnSubmit(del_course) db.SubmitChanges()
I have a strange problem. I am adding a LinqDatasource object, and set the context:
[Code]....
Then I get this error:The type 'System.Data.Linq.DataContext' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.
I want to do paging the API Membership without using the datacontrols, but I get this error "Unable to cast object of type '<TakeIterator>d__3a`1[System.Char]' to type 'System.Collections.IList'." when I do this,
Basically, what I did is that: I have a table in SQL database and some of data fields allow null. I built Objectdatasource through dataset. When I built update page using dataset. It generate the following error before showing the update page correctly. It seems I have issue to retrieve the null value from the database through using objectdatasource through dataset. Any suggestions?An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code
Im my MVC 3.0 Application, I created a helper like below;
[Code]....
And I used that helper in a linq query as below;
[Code]....
When I fire my app, it gives me the below error. LINQ to Entities does not recognize the method 'System.String GenerateURl(System.String)' method, and this method cannot be translated into a store expression. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NotSupportedException: LINQ to Entities does not recognize the method 'System.String GenerateURl(System.String)' method, and this method cannot be translated into a store expression. Source Error:
Line 43: public Blogs GetBlog(string urlstring) { Line 44: Line 45: return GetAll().SingleOrDefault(x => BlogUrlGeneration.GenerateURl(x.ArticleTitle).Equals(urlstring)); Line 46: } Line 47:
İn my blog, the link will be like below; [URL] so I need to set the above urlgenerator class into lambada. How can I do that? What would it take to make that work perfectly
I am trying to write a table output from SQL database to a gridview/ Data List through an Object Data Source. I am a new starter and your help will be useful.
public List<Staff> GetStaff() cmd.CommandType = SqlConnection con = new SqlConnection(connectionstring);SqlCommand cmd = new [code]...
I am trying to upload a picture into database using FormView insertItemTemplate. FormView is bounded by objectdatasource.To upload, I placed FileUpload control inside insertItemTemplate.In table the dataType is image.Error:Object of type 'System.Boolean' cannot be converted to type 'System.Byte[]'.
