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Class ExpressionHelper

A set of helper methods for dealing with expressions

Inheritance

System.Object

Namespace: Umbraco.Cms.Core

Assembly: Umbraco.Core.dll

Syntax

public static class ExpressionHelper

Methods

FindProperty(LambdaExpression)

Declaration

public static (MemberInfo, string) FindProperty(LambdaExpression lambda)

Parameters

Type	Name	Description
System.Linq.Expressions.LambdaExpression	lambda

Returns

Type	Description
System.ValueTuple<System.Reflection.MemberInfo, System.String>

GetFirstValueFromArguments(IEnumerable<Expression>)

Gets the first value from the supplied arguments of an expression, for those arguments that can be cast to System.Linq.Expressions.ConstantExpression.

Declaration

public static object GetFirstValueFromArguments(IEnumerable<Expression> arguments)

Parameters

Type	Name	Description
IEnumerable<System.Linq.Expressions.Expression>	arguments	The arguments.

Returns

Type	Description
System.Object

GetMember(Expression)

Gets a System.Reflection.MemberInfo from an System.Linq.Expressions.Expression provided it refers to member access.

Declaration

public static MemberInfo GetMember(Expression expression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression	expression	The expression.

Returns

Type	Description
System.Reflection.MemberInfo

GetMemberInfo<T, TReturn>(Expression<Func<T, TReturn>>)

Gets a System.Reflection.MemberInfo from an System.Linq.Expressions.Expression<TDelegate> of provided it refers to member access.

Declaration

public static MemberInfo GetMemberInfo<T, TReturn>(Expression<Func<T, TReturn>> fromExpression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression<Func<T, TReturn>>	fromExpression	From expression.

Returns

Type	Description
System.Reflection.MemberInfo	The System.Reflection.MemberInfo or null if fromExpression cannot be converted to System.Linq.Expressions.MemberExpression.

Type Parameters

Name	Description
T
TReturn	The type of the return.

GetMethod(Expression)

Gets a System.Reflection.MethodInfo from an System.Linq.Expressions.Expression provided it refers to a method call.

Declaration

public static MethodInfo GetMethod(Expression expression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression	expression	The expression.

Returns

Type	Description
System.Reflection.MethodInfo	The System.Reflection.MethodInfo or null if expression cannot be converted to System.Linq.Expressions.MethodCallExpression.

GetMethodInfo<T>(Expression<Action<T>>)

Gets a System.Reflection.MethodInfo from an System.Linq.Expressions.Expression<TDelegate> of provided it refers to a method call.

Declaration

public static MethodInfo GetMethodInfo<T>(Expression<Action<T>> fromExpression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression<Action<T>>	fromExpression	From expression.

Returns

Type	Description
System.Reflection.MethodInfo	The System.Reflection.MethodInfo or null if fromExpression is null or cannot be converted to System.Linq.Expressions.MethodCallExpression.

Type Parameters

Name	Description
T

GetMethodInfo<TReturn>(Expression<Func<TReturn>>)

Gets the method info.

Declaration

public static MethodInfo GetMethodInfo<TReturn>(Expression<Func<TReturn>> fromExpression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression<Func<TReturn>>	fromExpression	From expression.

Returns

Type	Description
System.Reflection.MethodInfo

Type Parameters

Name	Description
TReturn	The return type of the method.

GetMethodInfo<T1, T2>(Expression<Func<T1, T2>>)

Gets the method info.

Declaration

public static MethodInfo GetMethodInfo<T1, T2>(Expression<Func<T1, T2>> fromExpression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression<Func<T1, T2>>	fromExpression	From expression.

Returns

Type	Description
System.Reflection.MethodInfo

Type Parameters

Name	Description
T1	The type of the 1.
T2	The type of the 2.

GetMethodParams<T1, T2>(Expression<Func<T1, T2>>)

Declaration

public static IDictionary<string, object>? GetMethodParams<T1, T2>(Expression<Func<T1, T2>> fromExpression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression<Func<T1, T2>>	fromExpression

Returns

Type	Description
System.Nullable<IDictionary<System.String, System.Object>>

Type Parameters

Name	Description
T1
T2

GetPropertyInfo<TSource, TProperty>(TSource, Expression<Func<TSource, TProperty>>)

Gets a System.Reflection.PropertyInfo object from an expression.

Declaration

public static PropertyInfo GetPropertyInfo<TSource, TProperty>(this TSource source, Expression<Func<TSource, TProperty>> propertyLambda)

Parameters

Type	Name	Description
TSource	source	The source.
System.Linq.Expressions.Expression<Func<TSource, TProperty>>	propertyLambda	The property lambda.

Returns

Type	Description
System.Reflection.PropertyInfo

Type Parameters

Name	Description
TSource	The type of the source.
TProperty	The type of the property.

GetPropertyInfo<TSource, TProperty>(Expression<Func<TSource, TProperty>>)

Gets a System.Reflection.PropertyInfo object from an expression.

Declaration

public static PropertyInfo GetPropertyInfo<TSource, TProperty>(Expression<Func<TSource, TProperty>> propertyLambda)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression<Func<TSource, TProperty>>	propertyLambda	The property lambda.

Returns

Type	Description
System.Reflection.PropertyInfo

Type Parameters

Name	Description
TSource	The type of the source.
TProperty	The type of the property.

GetStaticMethodInfo(Delegate)

Gets a System.Reflection.MethodInfo from a

Declaration

public static MethodInfo GetStaticMethodInfo(Delegate fromMethodGroup)

Parameters

Type	Name	Description
Delegate	fromMethodGroup	From method group.

Returns

Type	Description
System.Reflection.MethodInfo

IsConstant(Expression)

Determines whether the specified expression is a constant.

Declaration

public static bool IsConstant(Expression expression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression	expression	The expression.

Returns

Type	Description
System.Boolean	true if the specified expression is constant; otherwise, false.

IsMember(Expression)

Determines whether the specified expression is a member.

Declaration

public static bool IsMember(Expression expression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression	expression	The expression.

Returns

Type	Description
System.Boolean	true if the specified expression is member; otherwise, false.

IsMethod(Expression)

Determines whether the specified expression is a method.

Declaration

public static bool IsMethod(Expression expression)

Parameters

Type	Name	Description
System.Linq.Expressions.Expression	expression	The expression.

Returns

Type	Description
System.Boolean	true if the specified expression is method; otherwise, false.

IsMethodSignatureEqualTo(MethodInfo, MethodInfo)

Determines whether the MethodInfo is the same based on signature, not based on the equality operator or HashCode.

Declaration

public static bool IsMethodSignatureEqualTo(this MethodInfo left, MethodInfo right)

Parameters

Type	Name	Description
System.Reflection.MethodInfo	left	The left.
System.Reflection.MethodInfo	right	The right.

Returns

Type	Description
System.Boolean	true if [is method signature equal to] [the specified left]; otherwise, false.

Remarks

This is useful for comparing Expression methods that may contain different generic types