Added new functions: replace and poke for inner xml

[jsauvexamarin]

Added new functions:

• XPathReplaceInnerText
• XmlPokeInnerText
• XPathReplaceInnerTextNS
• XmlPokeInnerTextNS

The existing XPathReplace and XmlPoke functions are incapable of modifying the Value property of XmlNode. This is due to both Mono and .NET throwing an InvalidOperationException in the body of the XmlNode.Value property setter:

Mono:
https://github.com/mosa/Mono-Class-Libraries/blob/master/mcs/class/System.XML/System.Xml/XmlNode.cs#L309

.NET:
https://github.com/Microsoft/referencesource/blob/master/System.Xml/System/Xml/Dom/XmlNode.cs#L92

I'm seeing that InvalidOperationException in practice in one of my FAKE build scripts. I know the XPath expression I'm using is valid; if I change it to be invalid, I get the "node not found" message. What I'm saying is: I'm definitely using XmlPoke properly, and it's throwing a new InvalidOperationException ("This node does not have a value") for any string value that I feed it.

So, I've added some functions that allow updating the InnerText value of a node; something for which I have a need in my FAKE build scripts. InnerText IS a mutable property, unlike Value.

Suggestion: Consider removing XPathReplace, XPathReplaceNS, XmlPoke, and XmlPokeNS. I'm not sure what purpose they serve, because they don't seem to work. XmlNode.Value is unsettable in both .NET and Mono.

Just to provide a concrete example of where I'm using this in a custom Android resources file:

<resources>
    <string name="GoogleMapsKey"></string>
</resources>

I want to update the value between the opening and closing string tags; the 'inner text' of the string node.

[jsauvexamarin]

Never mind. I just wrote a test for XmlPokeInnerText and it's failing. I'll get the tests working and add a commit.

[jsauvexamarin]

Okay! Added passing tests! XmlPokeInnerText and XmlPokeInnerTextNS should prove useful for anyone wanting to modify xml node inner text values in-place on a filesystem. Please merge this! Thanks!

[jsauvexamarin]

Crap. The AppVeyor build failed on the when_poking_xml_innertext test. That's odd, because it's passing locally. Maybe an encoding issue? Investigating.

[jsauvexamarin]

Another note on the existing XmlPoke and XmlPokeNS (as well as their backing "Replace" functions): maybe they should be renamed to XmlAttributePoke et al, because that seems to be the only thing they actually do...modify attribute values. Just a friendly suggestion! :)

[forki]

thx a lot

[jsauvexamarin]

My pleasure! Thx for maintaining this great project!