Expression.Like in C#

Question

eg: x=> x.Name = "g"

I have code block like this

public Expression<Func<TEntity, bool>> SearchExpression()
{
    var c = new ConstantExpression[_paramList.Count];
    var b = new BinaryExpression[_paramList.Count];
    BinaryExpression comparisonExpression = null;

    var entity = Expression.Parameter(typeof(TEntity));

    for (int i = 0; i < _paramList.Count; i++)
    {
        var value = Convert.ChangeType(_paramList[i].Item2 /*"g"*/, _paramList[i].Item3 /*System.String*/);
        c[i] = Expression.Constant(value); //"g"

        // PROBLEM IS HERE
        b[i] = Expression.Equal(Expression.Property(entity, _paramList[i].Item1 /*Name*/, c[i]);
        // PROBLEM IS HERE



    }
    _paramList.Clear();
    comparisonExpression = b.Aggregate(Expression.And);
    return Expression.Lambda<Func<TEntity, bool>>(comparisonExpression, entity);
}

works like charm but I need Expression.Like (Like "g" not Equal "g")

Expression.Like(Expression.Property(entity, _paramList[i].Item1), c[i])

but C# expression tree does not support Like method

UPDATE :

I wrote something like this :

Expression.Call(Expression.Property(entity, _paramList[i].Item1),
                typeof(String).GetMethod("Contains"), new Expression[] { c[i] });  

but I need BinaryExpression not MethodCallExpression

Answer 1

You can make your code work by adding an equals expression over the method call, like so:

    b[i] = Expression.Equal(
        Expression.Call(Expression.Property(entity, _paramList[i].Item1),
        typeof (String).GetMethod("Contains"), 
          new Expression[] {c[i]}), Expression.Constant(true));

In pseudo code this reads as:

b[i] = entity => entity.someProperty.Contains(c[i]) == true;

Which will return a binary expression for you.