public static Expression Unwrap(Expression expr)
{
var visitor = new ConditionUnwrapper();
var result = visitor.Visit(expr);
return(result);
}
protected Expression CatchNullReference(MethodCallExpression expr)
{
if (expr.Object == null)
{
return(expr);
}
if (!expr.Object.Type.IsValueType || expr.Object.Type.IsNullable())
{
var @null = Expression.Constant(null, expr.Object.Type);
var isNull = Expression.Equal(@null, expr.Object);
var exception = Expression.Constant(new NullReferenceException($"Object reference not set to an instance of an object calling method '{expr.Method.Name}' in expression '{ConditionUnwrapper.Unwrap(expr)}'. Consider using a ternary expression to specify conditional access."));
var @throw = Expression.Throw(exception);
var block = Expression.Block(@throw, Expression.Default(expr.Type));
var condition = Expression.Condition(isNull, block, expr);
return(condition);
}
else
{
return(expr);
}
}