/// <summary>
/// Extract a part of expression or sub-expression
/// </summary>
/// <typeparam name="T">The type of the expression which belong to</typeparam>
/// <param name="binaryExpression">The binary expression which will resolve</param>
/// <returns></returns>
private static List <WhereExpressionResult> Extract <T>(BinaryExpression binaryExpression)
{
List <WhereExpressionResult> expressionResults = new List <WhereExpressionResult>();
WhereExpressionResult expressionResult = new WhereExpressionResult();
if (
binaryExpression.NodeType == ExpressionType.Equal
||
binaryExpression.NodeType == ExpressionType.NotEqual
||
binaryExpression.NodeType == ExpressionType.LessThan
||
binaryExpression.NodeType == ExpressionType.GreaterThan
||
binaryExpression.NodeType == ExpressionType.LessThanOrEqual
||
binaryExpression.NodeType == ExpressionType.GreaterThanOrEqual)
{
if (binaryExpression.Left is MemberExpression)
{
MemberExpression memberExpression = binaryExpression.Left as MemberExpression;
if (memberExpression.Expression != null && memberExpression.Expression.Type == typeof(T))
{
expressionResult.MemberName = memberExpression.Member.Name; // Name
}
else
{
expressionResult.MemberName = (memberExpression.Expression as MemberExpression).Member.Name; // Name
expressionResult.SubProperty = memberExpression.Member.Name; // Name.Length (Name.Length == 3)
}
expressionResult.Condition = binaryExpression.NodeType; // ==
expressionResult.Value = (binaryExpression.Right as ConstantExpression).Value.ToString(); // Foo
expressionResult.SubPropertyArgumentType = binaryExpression.Right.Type;
expressionResults.Add(expressionResult);
}
else if (binaryExpression.Left is MethodCallExpression)
{
MethodCallExpression methodCallExpression = binaryExpression.Left as MethodCallExpression;
expressionResult.MemberName = (methodCallExpression.Object as MemberExpression).Member.Name; //Name
expressionResult.SubProperty = methodCallExpression.Method.Name; // ToLower
if (methodCallExpression.Arguments != null && methodCallExpression.Arguments.Any())
{
expressionResult.SubPropertyArguments.AddRange(methodCallExpression.Arguments.Select(x => (x as ConstantExpression).Value).ToList());
}
expressionResult.Condition = binaryExpression.NodeType; // ==
expressionResult.Value = (binaryExpression.Right as ConstantExpression).Value.ToString(); // Foo
expressionResult.SubPropertyArgumentType = binaryExpression.Right.Type;
expressionResults.Add(expressionResult);
}
}
else if (binaryExpression.NodeType == ExpressionType.OrElse)
{
expressionResults.Add(new WhereExpressionResult()
{
Parentheses = "("
}); // (
GetWhereExpressions <T>(binaryExpression.Left as BinaryExpression, expressionResults); // Name == Goo
expressionResults.Add(new WhereExpressionResult()
{
Condition = ExpressionType.Or
}); // Or
GetWhereExpressions <T>(binaryExpression.Right as BinaryExpression, expressionResults); // Year == 2020
expressionResults.Add(new WhereExpressionResult()
{
Parentheses = ")"
}); // )
}
else if (binaryExpression.NodeType == ExpressionType.AndAlso)
{
expressionResults.Add(new WhereExpressionResult()
{
Parentheses = "("
}); // (
GetWhereExpressions <T>(binaryExpression.Left as BinaryExpression, expressionResults); // (Name == Foo Or || Name == Goo)
expressionResults.Add(new WhereExpressionResult()
{
Condition = ExpressionType.And
}); // And
GetWhereExpressions <T>(binaryExpression.Right as BinaryExpression, expressionResults); // Year == 2020
expressionResults.Add(new WhereExpressionResult()
{
Parentheses = ")"
}); // )
}
return(expressionResults);
}
/// <summary>
/// Extract a part of expression or sub-expression
/// </summary>
/// <typeparam name="T">The type of the expression which belong to</typeparam>
/// <param name="methodCallExpression">The call of method expression which will resolve</param>
/// <returns></returns>
private static List <WhereExpressionResult> Extract <T>(MethodCallExpression methodCallExpression)
{
List <WhereExpressionResult> expressionResults = new List <WhereExpressionResult>();
if (methodCallExpression.NodeType == ExpressionType.Call && methodCallExpression.Object is MemberExpression) //x.Name.StartsWith(F) or stringListItems.Contains(x.Name)
{
WhereExpressionResult expressionResult = new WhereExpressionResult();
expressionResult.SubProperty = methodCallExpression.Method.Name;
if (methodCallExpression.Object is MemberExpression)
{
expressionResult.MemberName = (methodCallExpression.Object as MemberExpression).Member.Name; // x.Name.StartsWith(F) => "Name" or stringListItems.Contains(x.Name) => stringListItems
}
if (methodCallExpression.Arguments.FirstOrDefault() is MemberExpression)
{
expressionResult.MemberName = (methodCallExpression.Arguments.FirstOrDefault() as MemberExpression).Member.Name; // stringListItems.Contains(x.Name) => "Name"
}
MemberExpression memberExpression = methodCallExpression.Object as MemberExpression;
Expression subExpression = memberExpression.Expression;
string expressionParameterKeyword = memberExpression.Member.Name;
if (subExpression is ConstantExpression) //stringListItems.Contains(x.Name)
{
object subExpressionValue = (subExpression as ConstantExpression).Value;
if (methodCallExpression.Object.Type == typeof(List <string>))
{
List <string> values = subExpressionValue.GetType().GetField(expressionParameterKeyword).GetValue(subExpressionValue) as List <string>;
expressionResult.SubPropertyArgumentType = typeof(string);
expressionResult.SubPropertyArguments.AddRange(values); // stringListItems.Contains(x.Name) => elements of "stringListItems"
}
else if (methodCallExpression.Object.Type == typeof(List <int>))
{
List <int> values = subExpressionValue.GetType().GetField(expressionParameterKeyword).GetValue(subExpressionValue) as List <int>;
expressionResult.SubPropertyArgumentType = typeof(int);
expressionResult.SubPropertyArguments.AddRange(values.Select(x => x.ToString()).ToList());
}
}
else // x.Name.StartsWith(F)
{
if (methodCallExpression.Arguments.FirstOrDefault() is ConstantExpression)
{
ConstantExpression constantExpression = methodCallExpression.Arguments.FirstOrDefault() as ConstantExpression;
expressionResult.SubPropertyArgumentType = constantExpression.Value.GetType();
expressionResult.Value = constantExpression.Value.ToString(); // x.Name.StartsWith(F) => "F"
}
}
expressionResults.Add(expressionResult);
}
else if (methodCallExpression.NodeType == ExpressionType.Call && methodCallExpression.Method.DeclaringType == typeof(Enumerable)) //stringArrayItems.Contains(x.Name)
{
WhereExpressionResult expressionResult = new WhereExpressionResult();
expressionResult.SubProperty = methodCallExpression.Method.Name;
Expression parameterExpression = methodCallExpression.Arguments.FirstOrDefault(x => x is MemberExpression && (x as MemberExpression).Expression.NodeType == ExpressionType.Parameter);
expressionResult.MemberName = (parameterExpression as MemberExpression).Member.Name;
Expression constantExpression = methodCallExpression.Arguments.FirstOrDefault(x => x is MemberExpression && (x as MemberExpression).Expression.NodeType == ExpressionType.Constant);
MemberExpression memberExpression = constantExpression as MemberExpression;
string expressionParameterKeyword = memberExpression.Member.Name;
if (memberExpression.Type == typeof(string[]))
{
object values = (memberExpression.Expression as ConstantExpression).Value;
object items = values.GetType().GetField(expressionParameterKeyword).GetValue(values);
expressionResult.SubPropertyArguments.AddRange((items as string[])); // stringArrayItems.Contains(x.Name) => elements of "stringArrayItems"
expressionResult.SubPropertyArgumentType = typeof(string);
}
else if (memberExpression.Type == typeof(int[]))
{
object values = (memberExpression.Expression as ConstantExpression).Value;
object items = values.GetType().GetField(expressionParameterKeyword).GetValue(values);
expressionResult.SubPropertyArguments.AddRange((items as int[]).Select(x => x.ToString()).ToList());
expressionResult.SubPropertyArgumentType = typeof(int);
}
expressionResults.Add(expressionResult);
}
else if (methodCallExpression.NodeType == ExpressionType.Call)
{
WhereExpressionResult expressionResult = new WhereExpressionResult();
expressionResult.SubProperty = methodCallExpression.Method.Name;
expressionResult.MemberName = (methodCallExpression.Arguments.FirstOrDefault() as MemberExpression).Member.Name;
expressionResults.Add(expressionResult);
}
return(expressionResults);
}
