从具体化的“System.Int32”类型到“System.Double”类型的指定转换无效

Question

When executing the following query, I get the error:

The specified cast from a materialized 'System.Int32' type to the 'System.Double' type is not valid.

var data = ctx.tblTO
                   .Where(m => m.Id == Id)
                   .GroupBy(m => m.EmployeeId)
                   .Select(m => new
                   {
                       workDay = m.Sum(k => k.WorkDay),
                       onDutyDay = m.Sum(k => k.OnDutyDay),
                       holiDay = m.Sum(k => k.Holiday)
                   })
                   .FirstOrDefault();

The datatype of WorkDay , OnDutyDay and Holiday is double . There is no Int32 here, so why do I get this error?

How can I solve this error?

public class TO
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }           
    public int EmployeeId { get; set; }
    public double WorkDay { get; set; }
    public double OnDutyDay { get; set; }
    public double Holiday { get; set; }
}

Answer 1

I think the data type of the columns inside your database table is Int32 but your data model has double . You need to change the data types of your data models to int . By materialized it means the type it got when it ran the query on the database.

Answer 2

First make sure your model and table column data type are same.

Try to change your query to this.

var data = ctx.tblTO
           .Where(m => m.Id == Id)
           .GroupBy(m => m.EmployeeId)
           .Select(m => new
           {
               workDay = m.Select(k => k.WorkDay).DefaultIfEmpty(0).Sum(),
               onDutyDay = m.Select(k => k.OnDutyDay).DefaultIfEmpty(0).Sum(),
               holiDay = m.Select(k => k.Holiday).DefaultIfEmpty(0).Sum()
           })
           .FirstOrDefault();

If the collection is empty, it will return one element with the value of 0 and then the sum will be applied.

Answer 3

For me I was calling a stored procedure from EF 6 of which I wrote a poco, but I didn't write the sproc. I needed to look at all the tables that had field returning data types. and then change my Poco from a int to boolean.

public Boolean Active { get; set; }

Answer 4

Apart from the other answers, I got another scenario where I faced the same error. Which is, In our stored procedure a bigint was being casted to a decimal and on C# the same thing was being casted to int64. See:

SELECT Cast(@Request_Id as decimal) AS RetValue

What I did was changed the query to this:

SELECT @Request_Id AS RetValue

So, I removed the extra casting and the issue was gone. Somehow, it was maybe raising some sort of arithmetic exceptions but not quite sure yet. Will Update soon if I get to know the exact reason.

PS: My @Request_Id variable is of type bigint .

DECLARE @Request_Id bigint = 0