public static Func <TParameter, TResult?> CreateValueGetter <TParameter, TResult>(
[NotNull] Expression <Func <TParameter, TResult> > expression)
where TResult : struct
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
var parameters = expression.Parameters;
var body = ExpressionCreator.CreateValueBody(typeof(TResult?), expression.Body);
var lambda = Expression.Lambda <Func <TParameter, TResult?> >(body, parameters);
return(lambda.Compile());
}
public static Func <TParameter1, TParameter2, TResult> CreateGetter <TParameter1, TParameter2, TResult>(
[NotNull] Expression <Func <TParameter1, TParameter2, TResult> > expression,
TResult fallback)
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
var parameters = expression.Parameters;
var body = ExpressionCreator.CreateValueBody(typeof(TResult), expression.Body, Fallback(fallback));
var lambda = Expression.Lambda <Func <TParameter1, TParameter2, TResult> >(body, parameters);
return(lambda.Compile());
}
/// <summary>
/// Creates the getter.
/// </summary>
/// <typeparam name="TResult">The type of the result.</typeparam>
/// <param name="parameters">The parameters.</param>
/// <param name="expressionTree">The expression tree.</param>
/// <returns>The Getter.</returns>
/// <exception cref="ArgumentNullException">
/// parameters
/// or
/// expressionTree is null.
/// </exception>
public static Func <TResult> CreateGetter <TResult>(ReadOnlyCollection <ParameterExpression> parameters, IExpressionTree expressionTree)
{
if (parameters == null)
{
throw new ArgumentNullException(nameof(parameters));
}
if (expressionTree == null)
{
throw new ArgumentNullException(nameof(expressionTree));
}
var body = ExpressionCreator.CreateValueBody(typeof(TResult), expressionTree);
var lambda = Expression.Lambda <Func <TResult> >(body, parameters);
return(lambda.Compile());
}
public static Func <TParameter1, TParameter2, TResult?> CreateValueGetter <TParameter1, TParameter2, TResult>(
[NotNull] ReadOnlyCollection <ParameterExpression> parameters,
[NotNull] IExpressionTree expressionTree)
where TResult : struct
{
if (parameters == null)
{
throw new ArgumentNullException(nameof(parameters));
}
if (expressionTree == null)
{
throw new ArgumentNullException(nameof(expressionTree));
}
var body = ExpressionCreator.CreateValueBody(typeof(TResult?), expressionTree);
var lambda = Expression.Lambda <Func <TParameter1, TParameter2, TResult?> >(body, parameters);
return(lambda.Compile());
}