Serious Serialization problem

J

Johnny J.

I've made an inherited ListView control with a customized ColumnHeader Type.
I've overwritten the Columns property with a collection of my custom
ColumnHeader items. Now I would like to implement serialization so that
columns are persisted from designtime to runtime. But I cannot get it to
work.

I think it's because I don't know how to implement the type converter
correctly. Here's my suggestion for the type converter. Sample code for the
ListView, ColumnHeaderCollection and ColumnHeaderItem is supplied below. Can
anybody tell me what's wrong?

Cheers, Johnny J.



public class MyListViewColumnConverter : TypeConverter
{
public override bool CanConvertTo
(ITypeDescriptorContext context, Type destinationType)
{
if (destinationType == typeof(InstanceDescriptor))
{
return true;
}
return base.CanConvertTo(context, destinationType);
}
public override object ConvertTo(ITypeDescriptorContext context, CultureInfo
culture, object value, Type destinationType)
{
if (destinationType == typeof(InstanceDescriptor) && value is
MyListViewColumn)
{
MyListViewColumnitem = (MyListViewColumn)value;
ConstructorInfo ci = typeof(MyListViewColumn).GetConstructor(new Type[]
{ });
if (ci != null)
{
return new InstanceDescriptor(ci, null, false);
}
}
return base.ConvertTo(context, culture, value, destinationType);
}
}

**********************************************************
Listview, ColumnheaderCollection, ColumnHeaderItem code:


namespace MyListView
{
public class MyListView : ListView
{
private MyColumnHeaderCollection myListViewColumnHeaders = null;
public MyListView()
{
myListViewColumnHeaders = new MyColumnHeaderCollection(this);
//Other Code
}
public MyListView(IContainer container)
{
myListViewColumnHeaders = new MyColumnHeaderCollection(this);
container.Add(this);
//Other Code
}
[Localizable(true)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
[Editor("System.Windows.Forms.Design.ColumnHeaderCollectionEditor,
System.Design, Version=2.0.0.0, Culture=neutral,
PublicKeyToken=b03f5f7f11d50a3a", typeof(UITypeEditor))]
[MergableProperty(false)]
public new MyColumnHeaderCollection Columns
{
get { return myListViewColumnHeaders; }
}
//Other Code
}
[DesignTimeVisible(false)]
public class MyColumnHeaderCollection : ListView.ColumnHeaderCollection
{
private SortedList columnList = new SortedList();
public new MyListViewColumn this[int index]
{
get
{ return (MyListViewColumn)columnList.GetByIndex(index); }
}
public override ColumnHeader Add(string str, int width, HorizontalAlignment
textAlign)
{
MyListViewColumn column = new MyListViewColumn(str, width, textAlign);
this.Add(column);
return column;
}
public override int Add(ColumnHeader column)
{
return this.Add(new MyListViewColumn(column));
}
public override void AddRange(ColumnHeader[] values)
{
for (int index = 0; index < values.Length; index++)
{
this.Add(new MyListViewColumn(values[index]));
}
}
public int Add(MyListViewColumn column)
{
int retValue = base.Add(column);
columnList.Add(column.ColumnID, column);
return retValue;
}
public new void Remove(ColumnHeader column)
{
base.Remove(column);
columnList.Remove(((MyListViewColumn)column).ColumnID);
}
public new void RemoveAt(int index)
{
ColumnHeader column = this[index];
this.Remove(column);
}
public new void Clear()
{
base.Clear();
columnList.Clear();
}
}
[DesignTimeVisible(false)]
[TypeConverter(typeof(MyListViewColumnConverter))]
public class MyListViewColumn : ColumnHeader
{
private int m_ColumnID = 0;
private static int autoColumnID = 0;
public MyListViewColumn()
{
Initialize("", 60, HorizontalAlignment.Left);
}
public MyListViewColumn(string str, int width, HorizontalAlignment
textAlign)
{
Initialize(str, width, textAlign);
}
public MyListViewColumn(ColumnHeader column)
{
Initialize(column.Text, column.Width, column.TextAlign);
}
private void Initialize(string str, int width, HorizontalAlignment
textAlign)
{
base.Text = str;
base.Width = width;
base.TextAlign = textAlign;
m_ColumnID = autoColumnID++;
}
[Browsable(false)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
public int ColumnID
{
get { return m_ColumnID; }
}
}
}
 
J

Johnny J.

I discovered I had missed a [Serializable] attribute on the MyListViewColumn
class. But that doesn't help - I get the error message:
MyListViewColumnConverter is unable to convert 'MyListView.MyListViewColumn'
to 'System.ComponentModel.Design.Serialization.InstanceDescriptor'.

/Johnny J.





Johnny J. said:
I've made an inherited ListView control with a customized ColumnHeader
Type. I've overwritten the Columns property with a collection of my custom
ColumnHeader items. Now I would like to implement serialization so that
columns are persisted from designtime to runtime. But I cannot get it to
work.

I think it's because I don't know how to implement the type converter
correctly. Here's my suggestion for the type converter. Sample code for
the ListView, ColumnHeaderCollection and ColumnHeaderItem is supplied
below. Can anybody tell me what's wrong?

Cheers, Johnny J.



public class MyListViewColumnConverter : TypeConverter
{
public override bool CanConvertTo
(ITypeDescriptorContext context, Type destinationType)
{
if (destinationType == typeof(InstanceDescriptor))
{
return true;
}
return base.CanConvertTo(context, destinationType);
}
public override object ConvertTo(ITypeDescriptorContext context,
CultureInfo culture, object value, Type destinationType)
{
if (destinationType == typeof(InstanceDescriptor) && value is
MyListViewColumn)
{
MyListViewColumnitem = (MyListViewColumn)value;
ConstructorInfo ci = typeof(MyListViewColumn).GetConstructor(new Type[]
{ });
if (ci != null)
{
return new InstanceDescriptor(ci, null, false);
}
}
return base.ConvertTo(context, culture, value, destinationType);
}
}

**********************************************************
Listview, ColumnheaderCollection, ColumnHeaderItem code:


namespace MyListView
{
public class MyListView : ListView
{
private MyColumnHeaderCollection myListViewColumnHeaders = null;
public MyListView()
{
myListViewColumnHeaders = new MyColumnHeaderCollection(this);
//Other Code
}
public MyListView(IContainer container)
{
myListViewColumnHeaders = new MyColumnHeaderCollection(this);
container.Add(this);
//Other Code
}
[Localizable(true)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
[Editor("System.Windows.Forms.Design.ColumnHeaderCollectionEditor,
System.Design, Version=2.0.0.0, Culture=neutral,
PublicKeyToken=b03f5f7f11d50a3a", typeof(UITypeEditor))]
[MergableProperty(false)]
public new MyColumnHeaderCollection Columns
{
get { return myListViewColumnHeaders; }
}
//Other Code
}
[DesignTimeVisible(false)]
public class MyColumnHeaderCollection : ListView.ColumnHeaderCollection
{
private SortedList columnList = new SortedList();
public new MyListViewColumn this[int index]
{
get
{ return (MyListViewColumn)columnList.GetByIndex(index); }
}
public override ColumnHeader Add(string str, int width,
HorizontalAlignment textAlign)
{
MyListViewColumn column = new MyListViewColumn(str, width, textAlign);
this.Add(column);
return column;
}
public override int Add(ColumnHeader column)
{
return this.Add(new MyListViewColumn(column));
}
public override void AddRange(ColumnHeader[] values)
{
for (int index = 0; index < values.Length; index++)
{
this.Add(new MyListViewColumn(values[index]));
}
}
public int Add(MyListViewColumn column)
{
int retValue = base.Add(column);
columnList.Add(column.ColumnID, column);
return retValue;
}
public new void Remove(ColumnHeader column)
{
base.Remove(column);
columnList.Remove(((MyListViewColumn)column).ColumnID);
}
public new void RemoveAt(int index)
{
ColumnHeader column = this[index];
this.Remove(column);
}
public new void Clear()
{
base.Clear();
columnList.Clear();
}
}
[DesignTimeVisible(false)]
[TypeConverter(typeof(MyListViewColumnConverter))]
public class MyListViewColumn : ColumnHeader
{
private int m_ColumnID = 0;
private static int autoColumnID = 0;
public MyListViewColumn()
{
Initialize("", 60, HorizontalAlignment.Left);
}
public MyListViewColumn(string str, int width, HorizontalAlignment
textAlign)
{
Initialize(str, width, textAlign);
}
public MyListViewColumn(ColumnHeader column)
{
Initialize(column.Text, column.Width, column.TextAlign);
}
private void Initialize(string str, int width, HorizontalAlignment
textAlign)
{
base.Text = str;
base.Width = width;
base.TextAlign = textAlign;
m_ColumnID = autoColumnID++;
}
[Browsable(false)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
public int ColumnID
{
get { return m_ColumnID; }
}
}
}
Click to expand...
 

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