using System; using System.Reflection; namespace StardewModdingAPI.Framework.Reflection { /// <summary>A field obtained through reflection.</summary> /// <typeparam name="TValue">The field value type.</typeparam> internal class ReflectedField<TValue> : IReflectedField<TValue> { /********* ** Properties *********/ /// <summary>The type that has the field.</summary> private readonly Type ParentType; /// <summary>The object that has the instance field (if applicable).</summary> private readonly object Parent; /// <summary>The display name shown in error messages.</summary> private string DisplayName => $"{this.ParentType.FullName}::{this.FieldInfo.Name}"; /********* ** Accessors *********/ /// <summary>The reflection metadata.</summary> public FieldInfo FieldInfo { get; } /********* ** Public methods *********/ /// <summary>Construct an instance.</summary> /// <param name="parentType">The type that has the field.</param> /// <param name="obj">The object that has the instance field (if applicable).</param> /// <param name="field">The reflection metadata.</param> /// <param name="isStatic">Whether the field is static.</param> /// <exception cref="ArgumentNullException">The <paramref name="parentType"/> or <paramref name="field"/> is null.</exception> /// <exception cref="ArgumentException">The <paramref name="obj"/> is null for a non-static field, or not null for a static field.</exception> public ReflectedField(Type parentType, object obj, FieldInfo field, bool isStatic) { // validate if (parentType == null) throw new ArgumentNullException(nameof(parentType)); if (field == null) throw new ArgumentNullException(nameof(field)); if (isStatic && obj != null) throw new ArgumentException("A static field cannot have an object instance."); if (!isStatic && obj == null) throw new ArgumentException("A non-static field must have an object instance."); // save this.ParentType = parentType; this.Parent = obj; this.FieldInfo = field; } /// <summary>Get the field value.</summary> public TValue GetValue() { try { return (TValue)this.FieldInfo.GetValue(this.Parent); } catch (InvalidCastException) { throw new InvalidCastException($"Can't convert the {this.DisplayName} field from {this.FieldInfo.FieldType.FullName} to {typeof(TValue).FullName}."); } catch (Exception ex) { throw new Exception($"Couldn't get the value of the {this.DisplayName} field", ex); } } /// <summary>Set the field value.</summary> //// <param name="value">The value to set.</param> public void SetValue(TValue value) { try { this.FieldInfo.SetValue(this.Parent, value); } catch (InvalidCastException) { throw new InvalidCastException($"Can't assign the {this.DisplayName} field a {typeof(TValue).FullName} value, must be compatible with {this.FieldInfo.FieldType.FullName}."); } catch (Exception ex) { throw new Exception($"Couldn't set the value of the {this.DisplayName} field", ex); } } } }