I am building dynamic linq expressions which is working fine for a single entity.

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Asked: June 18, 20262026-06-18T01:46:09+00:00 2026-06-18T01:46:09+00:00

I am building dynamic linq expressions which is working fine for a single entity.

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I am building dynamic linq expressions which is working fine for a single entity.
For example:
I have a class called Employee and empeduinfo

public class Employee
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class EmpEduInfo
{
    public int Id { get; set; }
    public string Name  { get; set; }
    public int EmpId { get; set; }
}

I need to get all the the employees and empeduinfo class starts with “x”

I prepared expression for startswith(“x”)

var temp= entities.employees.Include("EmpEduInfo").Where(mydynamicexpression);

In this case it is filtering only parent table not on child.

I need to prepare generic expression so than i need to filter both parent and child objects dynamically.

Without using expression I know a solution:

var temp= (from ee in entities.Employee.Include("EmpEduInfo").Where(x => x.name.StartsWith("t"))                           
           where ee.EmpEduInfo.Where(x => x.name.StartsWith("t")).Count()>0                                
           select ee).ToList();

using expressions I am building generic expression to provide dynamic advance search rather than writing in each and every entity.

Here is my expression details

            // Get the method information for the String.StartsWith() method                
            MethodInfo mi = typeof(string).GetMethod("StartsWith", new Type[] { typeof(string) });
            // Build the parameter for the expression
            ParameterExpression  empparam= Expression.Parameter(typeof(employee), "ename");;
            // Build the member that was specified for the expression
            MemberExpression field = Expression.PropertyOrField(empparam, "name");
            // Call the String.StartsWith() method on the member
            MethodCallExpression startsWith = Expression.Call(field, mi, Expression.Constant("t"));                  
            var namelamda = Expression.Lambda<Func<employee, bool>>(startsWith, new ParameterExpression[] { empparam });
            var temp = entities.employees.Include("empedudetails").Where(namelamda).ToList();