Adding a new entry in the config in code

[venerable bede]

I have the following code which takes in a string representing an element in my settings/config file. It then returns the value of that element.

public string GetAppConfigValue(string SettingName)
{
            string sContents;
            ConfigurationSectionGroup grpApp = config.GetSectionGroup("applicationSettings");
            ClientSettingsSection secPropSet = (ClientSettingsSection)grpApp.Sections[sSettingsSection];
            secPropSet.SectionInformation.ForceSave = true;
            SettingElement elm = secPropSet.Settings.Get(SettingName);
            if (elm == null)
            {
                sContents = SettingName + " is missing!";
            }
            else
            {
                sContents = elm.Value.ValueXml.InnerText.Trim();
            }
            return sContents;
}

This all works fine but what I need to do is create this setting with a string "NOT AVAILABLE"if it is not there.

I think its something along the lines off :

SettingElement newElem = new SettingElement(SettingName, SettingsSerializeAs.String);
secPropSet.Settings.Add(newElem);
//How do i add "NOT AVAILABLE" to its value

The above code adds this to the config "<setting name="NEW_ATTRIBUTE" serializeAs="String" />" but it has no value and no closing tag " </setting>"
Man am I ever confused :-(

[wossname]

SettingElement has a Value property, you need to populate that appropriately before the Add() call. MSDN has lots of info about it.

[venerable bede]

Thanks Wossy.

I'm still having tons of trouble with this one though. I have the following :

SettingElement newElem = new SettingElement(SettingName, SettingsSerializeAs.String);
SettingValueElement setValue;
System.Xml.XmlNode xNode = new System.Xml.XmlNode();
xNode.Value = "TESTING";
setValue.ValueXml = xNode;
newElem.Value = setValue;
secPropSet.Settings.Add(newElem);

All i get is :

Cannot create an instance of the abstract class or interface 'System.Xml.XmlNode'

However the value of newElem requires something of XMLNode type.

[venerable bede]

I have managed to get a bit further :

SettingElement newElem = new SettingElement(SettingName, SettingsSerializeAs.String);
System.Xml.XmlDocument doc = new System.Xml.XmlDocument();
System.Xml.XmlNode n = doc.CreateNode(System.Xml.XmlNodeType.Text, "bigWoof", "");
SettingValueElement setValue = new SettingValueElement();
setValue.ValueXml = n; 
newElem.Value = setValue;
secPropSet.Settings.Add(newElem);

This code generates the following :

 <setting name="HELPURL" serializeAs="String">bigWoof</setting>

Note the lack of <value></value> tags.

When I try and read the element I get the following :
The configuration section cannot contain a CDATA or text element.

Man this is doing my head in.

[Lord_Rat]

I use my own class so I must confess I'm not used to the built in save settings functions you are using, but my class works pretty well. Here are the two functions in their entirety:

//Written by Keith Ratliff - if you use, please leave this comment in your code.
		static object oKey = new object();
		public static void SaveSetting(string sSetting, string sValue)
		{
			lock(oKey){
				string sFolder = System.Windows.Forms.Application.StartupPath;
				System.Xml.XmlDocument oXD = new System.Xml.XmlDocument();
				try{
				oXD.Load(sFolder + "/settings.xml");
				}catch(System.Exception)
				{
					string sNewSettings = @"<Root></Root>";
					oXD.LoadXml(sNewSettings);
				}
				if(oXD.DocumentElement.SelectSingleNode(sSetting) != null)
					oXD.DocumentElement.RemoveChild(oXD.DocumentElement.SelectSingleNode(sSetting));
				System.Xml.XmlNode oNode = oXD.CreateNode(System.Xml.XmlNodeType.Element.ToString().ToLower(), sSetting, "");
				oNode.InnerXml = sValue;
				oXD.DocumentElement.AppendChild(oNode);
				oXD.Save(sFolder + "/settings.xml");
			}
		}
		
		public static string GetSetting(string sSetting)
		{
			string sRet = "";
			bool bOK = true;
			lock(oKey){
				string sFolder = System.Windows.Forms.Application.StartupPath;
				System.Xml.XmlDocument oXD = new System.Xml.XmlDocument();
				try{
					oXD.Load(sFolder + "/settings.xml");
				}catch(System.Exception){
					sRet = "";
					bOK = false;
				}
				
				System.Xml.XmlNode oNode = null;
				if(bOK){
					oNode = oXD.DocumentElement.SelectSingleNode(sSetting);
					if(oNode == null) {
						sRet = "";
						bOK = false;
					}
				}
				
				if(bOK){
					sRet = oNode.InnerXml;
				}
			}
			return sRet;
		}

If you want the error message you are describing (when the node doesn't already exist at all) just change
if(oNode == null) {
sRet = "";
bOK = false;
}

to

if(oNode == null) {
sRet = "NOT AVAILABLE!";
bOK = false;
}

EDIT: Adding thread safety.

[Lord_Rat]

The above code adds this to the config "<setting name="NEW_ATTRIBUTE" serializeAs="String" />" but it has no value and no closing tag " </setting>"
Man am I ever confused :-(

Taking a second look at your original, I should probably point something out about XML.

When a tag has no data inside, it is allowed to close itself by having a slash before the closing ">"

For example:
<SampleTag></SampleTag>

is exactly the same as
<SampleTag />

Notice the "/>" in the second one? That means it closes itself.

HTH