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September 2, 2015 02:29
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A C# helper to read and write XML from and to objects
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using System; | |
using System.Linq; | |
using System.Linq.Expressions; | |
using System.Reflection; | |
using System.Xml.Linq; | |
namespace Nwazet.Commerce.Helpers { | |
public static class XmlHelper { | |
/// <summary> | |
/// Like Add, but chainable. | |
/// </summary> | |
/// <param name="el">The parent element.</param> | |
/// <param name="children">The elements to add.</param> | |
/// <returns>Itself</returns> | |
public static XElement AddEl(this XElement el, params XElement[] children) { | |
el.Add(children.Cast<object>()); | |
return el; | |
} | |
/// <summary> | |
/// Gets the string value of an attribute, and null if the attribute doesn't exist. | |
/// </summary> | |
/// <param name="el">The element.</param> | |
/// <param name="name">The name of the attribute.</param> | |
/// <returns>The string value of the attribute if it exists, null otherwise.</returns> | |
public static string Attr(this XElement el, string name) { | |
var attr = el.Attribute(name); | |
return attr == null ? null : attr.Value; | |
} | |
/// <summary> | |
/// Gets a typed value from an attribute. | |
/// </summary> | |
/// <typeparam name="T">The type of the value</typeparam> | |
/// <param name="el">The element.</param> | |
/// <param name="name">The name of the attribute.</param> | |
/// <returns>The attribute value</returns> | |
public static T Attr<T>(this XElement el, string name) { | |
var attr = el.Attribute(name); | |
var type = typeof (T); | |
if (attr == null || | |
((!type.IsValueType || Nullable.GetUnderlyingType(type) != null) && type != typeof(string) && | |
"null".Equals(attr.Value, StringComparison.Ordinal))) { | |
return default(T); | |
} | |
if (type == typeof (string)) { | |
return (T)(object)attr.Value; | |
} | |
if (type == typeof (int)) { | |
return (T)(object)(int) attr; // Pretty, eh? OK, if you're so smart, find a better way. I'm waiting. Seriously, I'd love to not do this. | |
} | |
if (type == typeof (bool)) { | |
return (T)(object)(bool)attr; | |
} | |
if (type == typeof (DateTime)) { | |
return (T)(object)(DateTime)attr; | |
} | |
if (type == typeof (double)) { | |
return (T)(object)(double)attr; | |
} | |
if (type == typeof (float)) { | |
return (T)(object)(float)attr; | |
} | |
if (type == typeof (decimal)) { | |
return (T)(object)(decimal)attr; | |
} | |
if (type == typeof (int?)) { | |
return (T)(object)(int?)attr; | |
} | |
if (type == typeof (bool?)) { | |
return (T)(object)(bool?)attr; | |
} | |
if (type == typeof (DateTime?)) { | |
return (T)(object)(DateTime?)attr; | |
} | |
if (type == typeof (double?)) { | |
return (T)(object)(double?)attr; | |
} | |
if (type == typeof (float?)) { | |
return (T)(object)(float?)attr; | |
} | |
if (type == typeof (decimal?)) { | |
return (T)(object)(decimal?)attr; | |
} | |
throw new InvalidCastException(String.Format("Couldn't find how to deserialize to type {0}.", type.Name)); | |
} | |
/// <summary> | |
/// Sets an attribute value. This is chainable. | |
/// </summary> | |
/// <typeparam name="T">The type of the value.</typeparam> | |
/// <param name="el">The element.</param> | |
/// <param name="name">The attribute name.</param> | |
/// <param name="value">The value to set.</param> | |
/// <returns>Itself</returns> | |
public static XElement Attr<T>(this XElement el, string name, T value) { | |
el.SetAttributeValue(name, value); | |
return el; | |
} | |
/// <summary> | |
/// Returns the text contents of a child element. | |
/// </summary> | |
/// <param name="el">The parent element.</param> | |
/// <param name="name">The name of the child element.</param> | |
/// <returns>The text for the child element, and null if it doesn't exist.</returns> | |
public static string El(this XElement el, string name) { | |
var childElement = el.Element(name); | |
return childElement == null ? null : childElement.Value; | |
} | |
/// <summary> | |
/// Creates and sets the value of a child element. This is chainable. | |
/// </summary> | |
/// <typeparam name="T">The type of the value.</typeparam> | |
/// <param name="el">The parent element.</param> | |
/// <param name="name">The name of the child element.</param> | |
/// <param name="value">The value to set.</param> | |
/// <returns>Itself</returns> | |
public static XElement El<T>(this XElement el, string name, T value) { | |
el.SetElementValue(name, value); | |
return el; | |
} | |
/// <summary> | |
/// Sets a property value from an attribute of the same name. | |
/// </summary> | |
/// <typeparam name="TTarget">The type of the target object.</typeparam> | |
/// <typeparam name="TProperty">The type of the target property</typeparam> | |
/// <param name="el">The element.</param> | |
/// <param name="target">The target object.</param> | |
/// <param name="targetExpression">The property expression.</param> | |
/// <returns>Itself</returns> | |
public static XElement FromAttr<TTarget, TProperty>(this XElement el, TTarget target, | |
Expression<Func<TTarget, TProperty>> targetExpression) { | |
var propertyInfo = GetPropertyInfo(targetExpression); | |
var name = propertyInfo.Name; | |
var attr = el.Attribute(name); | |
if (attr == null) return el; | |
propertyInfo.SetValue(target, el.Attr<TProperty>(name), null); | |
return el; | |
} | |
/// <summary> | |
/// Sets an attribute with the value of a property of the same name. | |
/// </summary> | |
/// <typeparam name="TTarget">The type of the object.</typeparam> | |
/// <typeparam name="TProperty">The type of the property.</typeparam> | |
/// <param name="el">The element.</param> | |
/// <param name="target">The object.</param> | |
/// <param name="targetExpression">The property expression.</param> | |
/// <returns>Itself</returns> | |
public static XElement ToAttr<TTarget, TProperty>(this XElement el, TTarget target, | |
Expression<Func<TTarget, TProperty>> targetExpression) { | |
var propertyInfo = GetPropertyInfo(targetExpression); | |
var name = propertyInfo.Name; | |
var val = propertyInfo.GetValue(target, null); | |
if (typeof (TProperty) == typeof (string)) { | |
el.Attr(name, (string) val); | |
} | |
else if (val == null) { | |
el.Attr(name, "null"); | |
} | |
else if (typeof (TProperty) == typeof (int)) { | |
el.Attr(name, (int) val); | |
} | |
else if (typeof (TProperty) == typeof (bool)) { | |
el.Attr(name, (bool) val); | |
} | |
else if (typeof (TProperty) == typeof (DateTime)) { | |
el.Attr(name, (DateTime) val); | |
} | |
else if (typeof (TProperty) == typeof (double)) { | |
el.Attr(name, (double) val); | |
} | |
else if (typeof (TProperty) == typeof (float)) { | |
el.Attr(name, (float) val); | |
} | |
else if (typeof (TProperty) == typeof (decimal)) { | |
el.Attr(name, (decimal) val); | |
} | |
else if (typeof (TProperty) == typeof (int?)) { | |
el.Attr(name, (int?) val); | |
} | |
else if (typeof (TProperty) == typeof (bool?)) { | |
el.Attr(name, (bool?) val); | |
} | |
else if (typeof (TProperty) == typeof (DateTime?)) { | |
el.Attr(name, (DateTime?) val); | |
} | |
else if (typeof (TProperty) == typeof (double?)) { | |
el.Attr(name, (double?) val); | |
} | |
else if (typeof (TProperty) == typeof (float?)) { | |
el.Attr(name, (float?) val); | |
} | |
else if (typeof (TProperty) == typeof (decimal?)) { | |
el.Attr(name, (decimal?) val); | |
} | |
return el; | |
} | |
public static PropertyInfo GetPropertyInfo<TContext, TProperty>(Expression<Func<TContext, TProperty>> expression) { | |
var memberExpression = expression.Body as MemberExpression; | |
if (memberExpression == null) | |
throw new InvalidOperationException("Expression is not a member expression."); | |
var propertyInfo = memberExpression.Member as PropertyInfo; | |
if (propertyInfo == null) throw new InvalidOperationException("Expression is not for a property."); | |
return propertyInfo; | |
} | |
/// <summary> | |
/// Gives context to an XElement, enabling chained property operations. | |
/// </summary> | |
/// <typeparam name="TContext">The type of the context.</typeparam> | |
/// <param name="el">The element.</param> | |
/// <param name="context">The context.</param> | |
/// <returns>The element with context.</returns> | |
public static XElementWithContext<TContext> With<TContext>(this XElement el, TContext context) { | |
return new XElementWithContext<TContext>(el, context); | |
} | |
public class XElementWithContext<TContext> { | |
public XElementWithContext(XElement element, TContext context) { | |
Element = element; | |
Context = context; | |
} | |
public XElement Element { get; private set; } | |
public TContext Context { get; private set; } | |
public static implicit operator XElement(XElementWithContext<TContext> elementWithContext) { | |
return elementWithContext.Element; | |
} | |
/// <summary> | |
/// Replaces the current context with a new one, enabling chained action on different objects. | |
/// </summary> | |
/// <typeparam name="TNewContext">The type of the new context.</typeparam> | |
/// <param name="context">The new context.</param> | |
/// <returns>A new XElementWithContext, that has the new context.</returns> | |
public XElementWithContext<TNewContext> With<TNewContext>(TNewContext context) { | |
return new XElementWithContext<TNewContext>(Element, context); | |
} | |
/// <summary> | |
/// Sets the value of a context property as an attribute of the same name on the element. | |
/// </summary> | |
/// <typeparam name="TProperty">The type of the property.</typeparam> | |
/// <param name="targetExpression">The property expression.</param> | |
/// <returns>Itself</returns> | |
public XElementWithContext<TContext> ToAttr<TProperty>( | |
Expression<Func<TContext, TProperty>> targetExpression) { | |
Element.ToAttr(Context, targetExpression); | |
return this; | |
} | |
/// <summary> | |
/// Gets an attribute on the element and sets the property of the same name on the context with its value. | |
/// </summary> | |
/// <typeparam name="TProperty">The type of the property.</typeparam> | |
/// <param name="targetExpression">The property expression.</param> | |
/// <returns>Itself</returns> | |
public XElementWithContext<TContext> FromAttr<TProperty>( | |
Expression<Func<TContext, TProperty>> targetExpression) { | |
Element.FromAttr(Context, targetExpression); | |
return this; | |
} | |
/// <summary> | |
/// Evaluates an attribute from an expression. | |
/// It's a nice strongly-typed way to read attributes. | |
/// </summary> | |
/// <typeparam name="TProperty">The type of the property.</typeparam> | |
/// <param name="expression">The property expression.</param> | |
/// <returns>The attribute, ready to be cast.</returns> | |
public TProperty Attr<TProperty>(Expression<Func<TContext, TProperty>> expression) { | |
var propertyInfo = GetPropertyInfo(expression); | |
var name = propertyInfo.Name; | |
return Element.Attr<TProperty>(name); | |
} | |
} | |
} | |
} |
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using System; | |
using System.Xml.Linq; | |
using NUnit.Framework; | |
using Nwazet.Commerce.Helpers; | |
namespace Nwazet.Commerce.Tests { | |
[TestFixture] | |
public class XmlHelperTests { | |
[Test] | |
public void StringToAttribute() { | |
var el = new XElement("data"); | |
el.Attr("foo", "bar"); | |
Assert.That(el.Attribute("foo").Value, Is.EqualTo("bar")); | |
} | |
[Test] | |
public void IntToAttribute() { | |
var el = new XElement("data"); | |
el.Attr("foo", 42); | |
Assert.That(el.Attribute("foo").Value, Is.EqualTo("42")); | |
} | |
[Test] | |
public void BoolToAttribute() { | |
var el = new XElement("data"); | |
el.Attr("foo", true); | |
el.Attr("bar", false); | |
Assert.That(el.Attribute("foo").Value, Is.EqualTo("true")); | |
Assert.That(el.Attribute("bar").Value, Is.EqualTo("false")); | |
} | |
[Test] | |
public void DateTimeToAttribute() { | |
var el = new XElement("data"); | |
el.Attr("foo", new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc)); | |
Assert.That(el.Attribute("foo").Value, Is.EqualTo("1970-05-21T13:55:21.934Z")); | |
} | |
[Test] | |
public void DoubleFloatDecimalToAttribute() { | |
var el = new XElement("data"); | |
el.Attr("double", 12.456D); | |
el.Attr("float", 12.457F); | |
el.Attr("decimal", 12.458M); | |
Assert.That(el.Attribute("double").Value, Is.EqualTo("12.456")); | |
Assert.That(el.Attribute("float").Value, Is.EqualTo("12.457")); | |
Assert.That(el.Attribute("decimal").Value, Is.EqualTo("12.458")); | |
} | |
[Test] | |
public void ReadAttribute() { | |
var el = XElement.Parse("<data foo=\"bar\"/>"); | |
Assert.That(el.Attr("foo"), Is.EqualTo("bar")); | |
Assert.That(el.Attr("bar"), Is.Null); | |
} | |
[Test] | |
public void SerializeObject() { | |
var target = new Target { | |
AString = "foo", | |
AnInt = 42, | |
ABoolean = true, | |
ADate = new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc), | |
ADouble = 12.345D, | |
AFloat = 23.456F, | |
ADecimal = 34.567M, | |
ANullableInt = 42, | |
ANullableBoolean = true, | |
ANullableDate = new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc), | |
ANullableDouble = 12.345D, | |
ANullableFloat = 23.456F, | |
ANullableDecimal = 34.567M | |
}; | |
var el = new XElement("data"); | |
el.With(target) | |
.ToAttr(t => t.AString) | |
.ToAttr(t => t.AnInt) | |
.ToAttr(t => t.ABoolean) | |
.ToAttr(t => t.ADate) | |
.ToAttr(t => t.ADouble) | |
.ToAttr(t => t.AFloat) | |
.ToAttr(t => t.ADecimal) | |
.ToAttr(t => t.ANullableInt) | |
.ToAttr(t => t.ANullableBoolean) | |
.ToAttr(t => t.ANullableDate) | |
.ToAttr(t => t.ANullableDouble) | |
.ToAttr(t => t.ANullableFloat) | |
.ToAttr(t => t.ANullableDecimal); | |
Assert.That(el.Attr("AString"), Is.EqualTo("foo")); | |
Assert.That(el.Attr("AnInt"), Is.EqualTo("42")); | |
Assert.That(el.Attr("ABoolean"), Is.EqualTo("true")); | |
Assert.That(el.Attr("ADate"), Is.EqualTo("1970-05-21T13:55:21.934Z")); | |
Assert.That(el.Attr("ADouble"), Is.EqualTo("12.345")); | |
Assert.That(el.Attr("AFloat"), Is.EqualTo("23.456")); | |
Assert.That(el.Attr("ADecimal"), Is.EqualTo("34.567")); | |
Assert.That(el.Attr("ANullableInt"), Is.EqualTo("42")); | |
Assert.That(el.Attr("ANullableBoolean"), Is.EqualTo("true")); | |
Assert.That(el.Attr("ANullableDate"), Is.EqualTo("1970-05-21T13:55:21.934Z")); | |
Assert.That(el.Attr("ANullableDouble"), Is.EqualTo("12.345")); | |
Assert.That(el.Attr("ANullableFloat"), Is.EqualTo("23.456")); | |
Assert.That(el.Attr("ANullableDecimal"), Is.EqualTo("34.567")); | |
} | |
[Test] | |
public void DeSerializeObject() { | |
var target = new Target(); | |
var el = | |
XElement.Parse( | |
"<data AString=\"foo\" AnInt=\"42\" ABoolean=\"true\" " + | |
"ADate=\"1970-05-21T13:55:21.934Z\" ADouble=\"12.345\" " + | |
"AFloat=\"23.456\" ADecimal=\"34.567\" " + | |
"ANullableInt=\"42\" ANullableBoolean=\"true\" " + | |
"ANullableDate=\"1970-05-21T13:55:21.934Z\" ANullableDouble=\"12.345\" " + | |
"ANullableFloat=\"23.456\" ANullableDecimal=\"34.567\"/>"); | |
el.With(target) | |
.FromAttr(t => t.AString) | |
.FromAttr(t => t.AnInt) | |
.FromAttr(t => t.ABoolean) | |
.FromAttr(t => t.ADate) | |
.FromAttr(t => t.ADouble) | |
.FromAttr(t => t.AFloat) | |
.FromAttr(t => t.ADecimal) | |
.FromAttr(t => t.ANullableInt) | |
.FromAttr(t => t.ANullableBoolean) | |
.FromAttr(t => t.ANullableDate) | |
.FromAttr(t => t.ANullableDouble) | |
.FromAttr(t => t.ANullableFloat) | |
.FromAttr(t => t.ANullableDecimal); | |
Assert.That(target.AString, Is.EqualTo("foo")); | |
Assert.That(target.AnInt, Is.EqualTo(42)); | |
Assert.That(target.ABoolean, Is.True); | |
Assert.That(target.ADate, Is.EqualTo(new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc))); | |
Assert.That(target.ADouble, Is.EqualTo(12.345D)); | |
Assert.That(target.AFloat, Is.EqualTo(23.456F)); | |
Assert.That(target.ADecimal, Is.EqualTo(34.567M)); | |
Assert.That(target.ANullableInt, Is.EqualTo(42)); | |
Assert.That(target.ANullableBoolean, Is.True); | |
Assert.That(target.ANullableDate, Is.EqualTo(new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc))); | |
Assert.That(target.ANullableDouble, Is.EqualTo(12.345D)); | |
Assert.That(target.ANullableFloat, Is.EqualTo(23.456F)); | |
Assert.That(target.ANullableDecimal, Is.EqualTo(34.567M)); | |
} | |
[Test] | |
public void DeSerializeFromMissingAttributeLeavesValueIntact() { | |
var target = new Target { | |
AString = "foo", | |
AnInt = 42, | |
ABoolean = true, | |
ADate = new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc), | |
ADouble = 12.345D, | |
AFloat = 23.456F, | |
ADecimal = 34.567M, | |
ANullableInt = 42, | |
ANullableBoolean = true, | |
ANullableDate = new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc), | |
ANullableDouble = 12.345D, | |
ANullableFloat = 23.456F, | |
ANullableDecimal = 34.567M | |
}; | |
var el = new XElement("data"); | |
el.With(target) | |
.FromAttr(t => t.AString) | |
.FromAttr(t => t.AnInt) | |
.FromAttr(t => t.ABoolean) | |
.FromAttr(t => t.ADate) | |
.FromAttr(t => t.ADouble) | |
.FromAttr(t => t.AFloat) | |
.FromAttr(t => t.ADecimal) | |
.FromAttr(t => t.ANullableInt) | |
.FromAttr(t => t.ANullableBoolean) | |
.FromAttr(t => t.ANullableDate) | |
.FromAttr(t => t.ANullableDouble) | |
.FromAttr(t => t.ANullableFloat) | |
.FromAttr(t => t.ANullableDecimal); | |
Assert.That(target.AString, Is.EqualTo("foo")); | |
Assert.That(target.AnInt, Is.EqualTo(42)); | |
Assert.That(target.ABoolean, Is.True); | |
Assert.That(target.ADate, Is.EqualTo(new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc))); | |
Assert.That(target.ADouble, Is.EqualTo(12.345D)); | |
Assert.That(target.AFloat, Is.EqualTo(23.456F)); | |
Assert.That(target.ADecimal, Is.EqualTo(34.567M)); | |
Assert.That(target.ANullableInt, Is.EqualTo(42)); | |
Assert.That(target.ANullableBoolean, Is.True); | |
Assert.That(target.ANullableDate, Is.EqualTo(new DateTime(1970, 5, 21, 13, 55, 21, 934, DateTimeKind.Utc))); | |
Assert.That(target.ANullableDouble, Is.EqualTo(12.345D)); | |
Assert.That(target.ANullableFloat, Is.EqualTo(23.456F)); | |
Assert.That(target.ANullableDecimal, Is.EqualTo(34.567M)); | |
} | |
[Test] | |
public void NullSerializes() { | |
var target = new Target(); | |
var el = new XElement("data"); | |
el.With(target) | |
.ToAttr(t => t.AString) | |
.ToAttr(t => t.ANullableInt) | |
.ToAttr(t => t.ANullableBoolean) | |
.ToAttr(t => t.ANullableDate) | |
.ToAttr(t => t.ANullableDouble) | |
.ToAttr(t => t.ANullableFloat) | |
.ToAttr(t => t.ANullableDecimal); | |
Assert.That(el.Attr("AString"), Is.Null); | |
Assert.That(el.Attr("ANullableInt"), Is.EqualTo("null")); | |
Assert.That(el.Attr("ANullableBoolean"), Is.EqualTo("null")); | |
Assert.That(el.Attr("ANullableDate"), Is.EqualTo("null")); | |
Assert.That(el.Attr("ANullableDouble"), Is.EqualTo("null")); | |
Assert.That(el.Attr("ANullableFloat"), Is.EqualTo("null")); | |
Assert.That(el.Attr("ANullableDecimal"), Is.EqualTo("null")); | |
} | |
[Test] | |
public void DeSerializeNull() { | |
var target = new Target(); | |
var el = | |
XElement.Parse( | |
"<data AString=\"null\" ANullableInt=\"null\" ANullableBoolean=\"null\" " + | |
"ANullableDate=\"null\" ANullableDouble=\"null\" " + | |
"ANullableFloat=\"null\" ANullableDecimal=\"null\"/>"); | |
el.With(target) | |
.FromAttr(t => t.AString) | |
.FromAttr(t => t.ANullableInt) | |
.FromAttr(t => t.ANullableBoolean) | |
.FromAttr(t => t.ANullableDate) | |
.FromAttr(t => t.ANullableDouble) | |
.FromAttr(t => t.ANullableFloat) | |
.FromAttr(t => t.ANullableDecimal); | |
Assert.That(target.AString, Is.EqualTo("null")); | |
Assert.That(target.ANullableInt, Is.Null); | |
Assert.That(target.ANullableBoolean, Is.Null); | |
Assert.That(target.ANullableDate, Is.Null); | |
Assert.That(target.ANullableDouble, Is.Null); | |
Assert.That(target.ANullableFloat, Is.Null); | |
Assert.That(target.ANullableDecimal, Is.Null); | |
} | |
private class Target { | |
public string AString { get; set; } | |
public int AnInt { get; set; } | |
public bool ABoolean { get; set; } | |
public DateTime ADate { get; set; } | |
public double ADouble { get; set; } | |
public float AFloat { get; set; } | |
public decimal ADecimal { get; set; } | |
public int? ANullableInt { get; set; } | |
public bool? ANullableBoolean { get; set; } | |
public DateTime? ANullableDate { get; set; } | |
public double? ANullableDouble { get; set; } | |
public float? ANullableFloat { get; set; } | |
public decimal? ANullableDecimal { get; set; } | |
} | |
} | |
} |
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Copy FromA C# helper to read and write XML from and to objects