typedobjectlistview.cs

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        public delegate String TypedCellToolTipGetterDelegate(OLVColumn column, T modelObject);

        public virtual TypedCellToolTipGetterDelegate CellToolTipGetter
        {
            set {
                if (value == null)
                    this.olv.CellToolTipGetter = null;
                else
                    this.olv.CellToolTipGetter = delegate(OLVColumn col, Object x) {
                        return value(col, (T)x);
                    };
            }
        }

        public virtual HeaderToolTipGetterDelegate HeaderToolTipGetter
        {
            get { return this.olv.HeaderToolTipGetter; }
            set { this.olv.HeaderToolTipGetter = value; }
        }

        //--------------------------------------------------------------------------------------
        // Commands

        /// <summary>
        /// This method will generate AspectGetters for any column that has an AspectName.
        /// </summary>
        public virtual void GenerateAspectGetters()
        {
            for (int i = 0; i < this.ListView.Columns.Count; i++)
                this.GetColumn(i).GenerateAspectGetter();
        }
    }

    /// <summary>
    /// A type-safe wrapper around an OLVColumn
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public class TypedColumn<T> where T : class
    {
        public TypedColumn(OLVColumn column)
        {
            this.column = column;
        }
        private OLVColumn column;

        public delegate Object TypedAspectGetterDelegate(T rowObject);
        public delegate void TypedAspectPutterDelegate(T rowObject, Object newValue);
        public delegate Object TypedGroupKeyGetterDelegate(T rowObject);
        public delegate Object TypedImageGetterDelegate(T rowObject);

        public TypedAspectGetterDelegate AspectGetter
        {
            get { return this.aspectGetter; }
            set {
                this.aspectGetter = value;
                if (value == null)
                    this.column.AspectGetter = null;
                else
                    this.column.AspectGetter = delegate(object x) {
                        return this.aspectGetter((T)x);
                    };
            }
        }
        private TypedAspectGetterDelegate aspectGetter;

        public TypedAspectPutterDelegate AspectPutter
        {
            get { return aspectPutter; }
            set {
                this.aspectPutter = value;
                if (value == null)
                    this.column.AspectPutter = null;
                else
                    this.column.AspectPutter = delegate(object x, object newValue) {
                        this.aspectPutter((T)x, newValue);
                    };
            }
        }
        private TypedAspectPutterDelegate aspectPutter;

        public TypedImageGetterDelegate ImageGetter
        {
            get { return imageGetter; }
            set {
                this.imageGetter = value;
                if (value == null)
                    this.column.ImageGetter = null;
                else
                    this.column.ImageGetter = delegate(object x) {
                        return this.imageGetter((T)x);
                    };
            }
        }
        private TypedImageGetterDelegate imageGetter;

        public TypedGroupKeyGetterDelegate GroupKeyGetter
        {
            get { return groupKeyGetter; }
            set {
                this.groupKeyGetter = value;
                if (value == null)
                    this.column.GroupKeyGetter = null;
                else
                    this.column.GroupKeyGetter = delegate(object x) {
                        return this.groupKeyGetter((T)x);
                    };
            }
        }
        private TypedGroupKeyGetterDelegate groupKeyGetter;

        #region Dynamic methods

        /// <summary>
        /// Generate an aspect getter that does the same thing as the AspectName,
        /// except without using reflection.
        /// </summary>
        /// <remarks>
        /// <para>
        /// If you have an AspectName of "Owner.Address.Postcode", this will generate
        /// the equivilent of: <code>this.AspectGetter = delegate (object x) {
        ///     return x.Owner.Address.Postcode;
        /// }
        /// </code>
        /// </para>
        /// <para>
        /// If AspectName is empty, this method will do nothing, otherwise 
        /// this will replace any existing AspectGetter.
        /// </para>
        /// </remarks>
        public void GenerateAspectGetter()
        {
            if (!String.IsNullOrEmpty(this.column.AspectName))
                this.AspectGetter = this.GenerateAspectGetter(typeof(T), this.column.AspectName);
        }

        /// <summary>
        /// Generates an aspect getter method dynamically. The method will execute
        /// the given dotted chain of selectors against a model object given at runtime.
        /// </summary>
        /// <param name="type">The type of model object to be passed to the generated method</param>
        /// <param name="path">A dotted chain of selectors. Each selector can be the name of a 
        /// field, property or parameter-less method.</param>
        /// <returns>A typed delegate</returns>
        private TypedAspectGetterDelegate GenerateAspectGetter(Type type, string path)
        {
            DynamicMethod getter = new DynamicMethod(String.Empty,
                typeof(Object), new Type[] { type }, type, true);
            this.GenerateIL(type, path, getter.GetILGenerator());
            return (TypedAspectGetterDelegate)getter.CreateDelegate(typeof(TypedAspectGetterDelegate));
        }

        /// <summary>
        /// This method generates the actual IL for the method.
        /// </summary>
        /// <param name="type"></param>
        /// <param name="path"></param>
        /// <param name="il"></param>
        private void GenerateIL(Type type, string path, ILGenerator il)
        {
            // Push our model object onto the stack
            il.Emit(OpCodes.Ldarg_0);

            // Generate the IL to access each part of the dotted chain
            string[] parts = path.Split('.');
            for (int i = 0; i < parts.Length; i++ ) {
                type = this.GeneratePart(il, type, parts[i], (i==parts.Length-1));
                if (type == null)
                    break;
            }

            // If the object to be returned is a value type (e.g. int, bool), it
            // must be boxed, since the delegate returns an Object
            if (type != null && type.IsValueType && !typeof(T).IsValueType)
                il.Emit(OpCodes.Box, type);

            il.Emit(OpCodes.Ret);
        }

        private Type GeneratePart(ILGenerator il, Type type, string pathPart, bool isLastPart)
        {
            // TODO: Generate check for null

            // Find the first member with the given nam that is a field, property, or parameter-less method
            List<MemberInfo> infos = new List<MemberInfo>(type.GetMember(pathPart));
            MemberInfo info = infos.Find(delegate(MemberInfo x) {
                if (x.MemberType == MemberTypes.Field || x.MemberType == MemberTypes.Property)
                    return true;
                if (x.MemberType == MemberTypes.Method)
                    return ((MethodInfo)x).GetParameters().Length == 0;
                else
                    return false;
            });
                        
            // If we couldn't find anything with that name, pop the current result and return an error
            if (info == null) {
                il.Emit(OpCodes.Pop);
                il.Emit(OpCodes.Ldstr, String.Format("'{0}' is not a parameter-less method, property or field of type '{1}'", pathPart, type.FullName));
                return null;
            }

            // Generate the correct IL to access the member. We remember the type of object that is going to be returned
            // so that we can do a method lookup on it at the next iteration
            Type resultType = null;
            switch (info.MemberType) {
                case MemberTypes.Method:
                    MethodInfo mi = (MethodInfo)info;
                    if (mi.IsVirtual)
                        il.Emit(OpCodes.Callvirt, mi);
                    else
                        il.Emit(OpCodes.Call, mi);
                    resultType = mi.ReturnType;
                    break;
                case MemberTypes.Property:
                    PropertyInfo pi = (PropertyInfo)info;
                    il.Emit(OpCodes.Call, pi.GetGetMethod());
                    resultType = pi.PropertyType;
                    break;
                case MemberTypes.Field:
                    FieldInfo fi = (FieldInfo)info;
                    il.Emit(OpCodes.Ldfld, fi);
                    resultType = fi.FieldType;
                    break;
            }

            // If the method returned a value type, and something is going to call a method on that value,
            // we need to load its address onto the stack, rather than the object itself.
            if (resultType.IsValueType && !isLastPart) {
                LocalBuilder lb = il.DeclareLocal(resultType);
                il.Emit(OpCodes.Stloc, lb);
                il.Emit(OpCodes.Ldloca, lb);
            } 

            return resultType;
        }

        #endregion
    }
}