Using ToString method at first in Expression Tree

Question

I'm new to expression Tree and I need to convert the below lambda to Expression Tree

Data.Where(s => s.Property.ToString().StartsWith("My Search Data"));

However I have done upto

Data.Where(s => s.Property.StartsWith("My Search Data");

Now I Need to use the ToString Method before Using StartsWith.

Below is my sample code.

ParameterExpression e = Expression.Parameter(typeof(T), "e");
PropertyInfo propertyInfo = typeof(T).GetProperty(field);
MemberExpression m = Expression.MakeMemberAccess(e, propertyInfo);
ConstantExpression c = Expression.Constant(data, typeof(string));
MethodInfo mi = typeof(string).GetMethod("StartsWith", new Type[] { typeof(string) });
Expression call = Expression.Call(m, mi, c);
Expression<Func<T, bool>> lambda = Expression.Lambda<Func<T, bool>>(call, e);
query = query.Where(lambda);

Answer 1

The ideea is that you have to get "ToString" method from System.Object. Because it is a virtual method, the Runtime can dispatch the call on your real object.

Note: IData is your whatever data that has a property named "Property".

ParameterExpression e = Expression.Parameter(typeof(IData), "e");
PropertyInfo propertyInfo = typeof(IData).GetProperty("Property");
MemberExpression m = Expression.MakeMemberAccess(e, propertyInfo);

var toString = typeof (Object).GetMethod("ToString");

ConstantExpression c = Expression.Constant(data, typeof(string));
MethodInfo mi = typeof(string).GetMethod("StartsWith", new Type[] { typeof(string) });

var toStringValue = Expression.Call(m, toString);

Expression call = Expression.Call(toStringValue, mi, c);

Expression<Func<IData, bool>> lambda = Expression.Lambda<Func<IData, bool>>(call, e);