Complex data types in User-scoped ApplicationSett ings

[Dave Booker]

How are complex data types saved and restored when used as User-scoped
Application Settings? For an example of what I'm trying to do that does not
work, take the following:

A project has a user-scoped Settings object called "TestString s" which is of
type "StringDictiona ry". The following code is run:

if (Settings.Defau lt.TestStrings == null)
Settings.Defaul t.TestStrings = new StringDictionar y();
Settings.Defaul t.TestStrings.A dd("Test", "Value");
Settings.Defaul t.Save();

Stepping through that code reveals that at each line, the proper action is
performed successfully -- TestStrings is instantiated as a new dictionary,
and a new KeyValuePair is added to it. But each time this program is run,
TestString is *always* null. Other string variables stored in the same
Settings instance are loaded and saved correctly, but TestStrings is not.

Are there any special tricks to dealing with complex objects in
ApplicationSett ings?

[Walter Wang [MSFT]]

Hi,

Thank you for posting!

The problem that StringDictionar y type settings is not saved is because it
doesn't have a TypeConverter and not xml serializable.

There are two primary mechanisms that ApplicationSett ingsBase uses to
serialize settings:
1) If a TypeConverter exists that can convert to and from string, we use it.
2) If not, we fallback to the XmlSerializer.

Here we can derive a custom type from StringDictionar y and either implement
a TypeConverter for it or implement IXmlSerializabl e.

Following is a sample which implements IXmlSerializabl e:

public class SerializableStr ingDictionary : StringDictionar y,
IXmlSerializabl e
{

#region Node class
[Serializable]
public class Node
{
public Node()
{ }

public Node(string k, string v)
{
key = k;
val = v;
}

public string key;
public string val;
}

#endregion Node class for XML Serialization

#region IXmlSerializabl e Members

public System.Xml.Sche ma.XmlSchema GetSchema()
{
return null;
}

public void ReadXml(System. Xml.XmlReader reader)
{
XmlSerializer x = new
XmlSerializer(t ypeof(System.Co llections.Array List), new System.Type[] {
typeof(Node) });

reader.Read();
ArrayList list = x.Deserialize(r eader) as ArrayList;

if (list == null)
return;

foreach (Node node in list)
{
Add(node.key, node.val);
}
}

public void WriteXml(System .Xml.XmlWriter writer)
{
XmlSerializer x = new
XmlSerializer(t ypeof(System.Co llections.Array List), new System.Type[] {
typeof(Node) });
ArrayList list = new ArrayList();
foreach (string key in this.Keys)
{
list.Add(new Node(key, this[key]));
}
x.Serialize(wri ter, list);
}

#endregion
}
Hope this helps.

Regards,

Walter Wang
Microsoft Online Community Support

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[Rafael]

I'am have the same problem.

Do us have the example in VB.NET or have other solution?

I need urgent this.

Best Regards.
_______________ _______________ ________

"Walter Wang [MSFT]" wrote:

Hi,

Thank you for posting!

The problem that StringDictionar y type settings is not saved is because it
doesn't have a TypeConverter and not xml serializable.

There are two primary mechanisms that ApplicationSett ingsBase uses to
serialize settings:
1) If a TypeConverter exists that can convert to and from string, we use it.
2) If not, we fallback to the XmlSerializer.

Here we can derive a custom type from StringDictionar y and either implement
a TypeConverter for it or implement IXmlSerializabl e.

Following is a sample which implements IXmlSerializabl e:

public class SerializableStr ingDictionary : StringDictionar y,
IXmlSerializabl e
{

#region Node class
[Serializable]
public class Node
{
public Node()
{ }

public Node(string k, string v)
{
key = k;
val = v;
}

public string key;
public string val;
}

#endregion Node class for XML Serialization

#region IXmlSerializabl e Members

public System.Xml.Sche ma.XmlSchema GetSchema()
{
return null;
}

public void ReadXml(System. Xml.XmlReader reader)
{
XmlSerializer x = new
XmlSerializer(t ypeof(System.Co llections.Array List), new System.Type[] {
typeof(Node) });

reader.Read();
ArrayList list = x.Deserialize(r eader) as ArrayList;

if (list == null)
return;

foreach (Node node in list)
{
Add(node.key, node.val);
}
}

public void WriteXml(System .Xml.XmlWriter writer)
{
XmlSerializer x = new
XmlSerializer(t ypeof(System.Co llections.Array List), new System.Type[] {
typeof(Node) });
ArrayList list = new ArrayList();
foreach (string key in this.Keys)
{
list.Add(new Node(key, this[key]));
}
x.Serialize(wri ter, list);
}

#endregion
}
Hope this helps.

Regards,

Walter Wang
Microsoft Online Community Support

=============== =============== =============== =====
When responding to posts, please "Reply to Group" via your newsreader so
that others may learn and benefit from your issue.
=============== =============== =============== =====

This posting is provided "AS IS" with no warranties, and confers no rights.