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WinForms FAQ - General IO

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There is no direct support in the framework to do this. You have to use the GetShortPathName function using PInvoke.

This is how the signature for this function looks like:


[DllImport(''kernel32.dll'', SetLastError=true, CharSet=CharSet.Auto)]
    public  static extern int  GetShortPathName(string  longPath, [MarshalAs(UnmanagedType.LPTStr)]StringBuilder  ShortPath, [MarshalAs(UnmanagedType.U4)]int  bufferSize);

Download C# Sample GetShortPathName.zip
Download VB.NET sample GetShortPathName_VB.zip

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Use the WebRequest class found in the System.Net namespace.

	//create the request object
	WebRequest req =  WebRequest.Create(@'http://www.syncfusion.com');

	//get the response and use the response
	WebResponse resp = req.GetResponse();
	Stream stream = resp.GetResponseStream();
	StreamReader sr = new StreamReader(stream);
	string s = sr.ReadToEnd();
	textBox1.Text = s;
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This is usually an issue when a newer version introduces newer names, then the older version will not serialize property due to the absence of certain names. For example, this code will fail, sometimes:


protected MyClassConstructor(SerializationInfo info, StreamingContext context)
{
	...
	// This might fail if MyProp was added in a newer version and you are serializing an older version.
	this.MyProp = info.GetBoolean('MyProp');
}

To avoid such conflicts, you could insert version nos. into the serialized info. and during deserialization check for a name only when a particular version is being deserialized. Or you could instead parse through the available info in the SerializationInfo list as follows:


[C#]
protected MyClassConstructor(SerializationInfo info, StreamingContext context)
{
	foreach(SerializationEntry entry in info)
	{
		switch(entry.Name)
		{
			case 'MyProp':
			// This will make sure that older versions without the MyProp name will also deserialize without any problems
			this.MyProp = (bool)entry.Value;
			break;
			...
		}
	}

}

[VB.Net]
Protected MyClassConstructor(ByVal info As SerializationInfo, ByVal context As StreamingContext) As Protected
	Dim entry As SerializationEntry
	For Each entry In info
		Select Case entry.Name
			Case 'MyProp'
			’ This will make sure that older versions without the MyProp name will also deserialize without any problems
			Me.MyProp = (Boolean)entry.Value
			Exit For
 
		End Select
	Next
 
End Function
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This is possible in this case: Say your object graph contains an object A, which has a reference to the object B. Then while deserializing A, the reference B might not be initialized yet. This is because while deserializing, references are deserialized one at a time and when A is deserialized, B might not have been deserialized, yet. You should follow the workaround as follows:


[C#]
protected MyCustomConstrucotr(SerializationInfo info, StreamingContext context)
{
	this.cachedRefToB = (B)info.GetValue('B', typeof(B));
	// At this point cachedRefToB might not be initialized.
}
// But when this method gets called, after complete serialization, the cachedRefToB will be initialized
void IDeserializationCallback.OnDeserialization(object sender)
{
	// At this point cachedRefToB will be initialized.
}

[VB.Net]
protected MyCustomConstrucotr(ByVal info As SerializationInfo, ByVal context As StreamingContext) As Protected
	Me.cachedRefToB = CType(info.GetValue('B', Type.GetType(B)), B)
	’ At this point cachedRefToB might not be initialized.
End Function

’ But when this method gets called, after complete serialization, the cachedRefToB will be initialized
’ Your class should implement IDeserializationCallback
Sub OnDeserialization(ByVal sender As Object) as IDeserializationCallback.OnDeserialization
	’ At this point cachedRefToB will be initialized.
End Sub
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Yes. This may not be the most efficient way to read from a ini file but it is a pretty good solution that is easy to maintain.

You can use a XML file to store your settings. Use a DataSet to read from it. Consider a simple sample file, config.ini. It has three parameters base_path, update_path and output_file. These will map to columns in the settings datatable.

view config.ini


// add error handling
DataSet ds = new DataSet();
			ds.ReadXml('config.ini', XmlReadMode.Auto);
			
			DataTable table = ds.Tables['settings'];
			DataRow row = table.Rows[0];
				
			string baseFolder = (string)row['base_path'];
			string updateFolder = (string)row['update_path'];
			string outputFileName = (string)row['output_file'];

You can of course use XmlReader, XmlDocument etc to create and maintain more complex ini files. But this is a quick way to maintain a simple property set.

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To store an object in the registry, the object should be serializable (either has a Serializable attribute attached to it or derives from ISerializable; same holds to all contained objects).

	ArrayList names;	// Source object; Can contain any object that is serializable
	... // Fill up this arraylist

	BinaryFormatter formatter = new BinaryFormatter();
	MemoryStream stream1 = new MemoryStream();
	formatter.Serialize(stream1, names);

	RegistryKey regKey;
	... // Open the key where you want to store it, with write permissions
	regKey.SetValue('ValueName', stream1.ToArray());
	
	To Read from registry:
	ArrayList names;	// Destination object
	RegKey regKey;
	...	// Open the corresponding key

	BinaryFormatter formatter = new BinaryFormatter();
	MemoryStream stream1 = new MemoryStream();
	
	byte[] barray1 = null;
	barray1 = (byte[])regKey.GetValue('ValueName');
	if(barray1 != null)
	{
		stream1.Write(barray1, 0, barray1.Length);
		MemoryStream stream1 = new MemoryStream();
	
		byte[] barray1 = null;
		barray1 = (byte[])regKey.GetValue('ValueName');
		if(barray1 != null)
		{
			stream1.Write(barray1, 0, barray1.Length);
			stream1.Position = 0;
		names = formatter.Deserialize(stream1) as ArrayList;
	}
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