CODEWITHSUNDEEP
asp.net-core
Hasni Mehdi
Hasni Mehdi

Reputation: 656

Exception : The binary operator AndAlso is not defined for the types 'System.Boolean

I am using Lamda expressing to combine condition for Where clause in enity framework This is my code : The binary operator AndAlso is not defined for the types 'System.Boolean

private Expression<Func<Transaction, bool>> BuildFilter(MovementFilterModel filterModel)
{
    Expression<Func<Transaction, bool>> expr = c => true;
    if (filterModel.BankAccounts.Count > 0)
    {
        foreach (var bank in filterModel.BankAccounts)
        {
            Expression<Func<Transaction, bool>> newPred = c => c.BankAccountId == Guid.Parse(bank);
            expr = Expression.Lambda<Func<Transaction, bool>>(Expression.AndAlso(expr, newPred), expr.Parameters);
        }
    }
    if (filterModel.Type == Enum.MovementType.EXPENSES)
    {
        Expression<Func<Transaction, bool>> newPred = c => c.Amount < 0;
        expr = Expression.Lambda<Func<Transaction, bool>>(Expression.AndAlso(expr.Body, newPred), expr.Parameters);
    }
    else if (filterModel.Type == Enum.MovementType.INCOME)
    {
        Expression<Func<Transaction, bool>> newPred = c => c.Amount >= 0;
        expr = Expression.Lambda<Func<Transaction, bool>>(Expression.AndAlso(expr, newPred), expr.Parameters);
    }
    if (filterModel.StartDate != null)
    {
        Expression<Func<Transaction, bool>> newPred = c => c.MadeOn >= filterModel.StartDate;
        expr = Expression.Lambda<Func<Transaction, bool>>(Expression.AndAlso(expr, newPred), expr.Parameters);
    }
    if (filterModel.EndDate != null)
    {
        Expression<Func<Transaction, bool>> newPred = c => c.MadeOn <= filterModel.EndDate;
        expr = Expression.Lambda<Func<Transaction, bool>>(Expression.AndAlso(expr, newPred), expr.Parameters);
    }
    if (filterModel.Category.Subcategories.Count > 0)
    {
        foreach (var subc in filterModel.Category.Subcategories)
        {
            Expression<Func<Transaction, bool>> newPred = c => c.SubCategoryId == Guid.Parse(subc);
            expr = Expression.Lambda<Func<Transaction, bool>>(Expression.AndAlso(expr, newPred), expr.Parameters);
        }
    }
    return expr;
}

When i call the function i get the exception : The binary operator AndAlso is not defined for the types 'System.Boolean. Any Solution please

Upvotes: 0

Views: 3811

Answers (1)

crgolden
crgolden

Reputation: 4634

Try changing from this:

expr = Expression.Lambda<Func<Transaction, bool>>(Expression.AndAlso(expr.Body, newPred), expr.Parameters);

To this:

expr = Expression.Lambda<Func<Transaction, bool>>(Expression.AndAlso(expr, newPred), expr.Parameters);

(Change expr.Body to expr)

Upvotes: 3

Related Questions