databindings

[frazer]

hi i have the following code in my project

ArrayList pictures = (new Pictures()).GetAllPictures();
allPictures.DataSource = pictures;
allPictures.DisplayMember = "pictures.ToString()"; //pictures.ToString
returns the names of the pictures.
allPictures.ValueMember = "pictures.Bitmap"; //this returns the
actual picture. and i get the foll error here

private void allPictures_SelectedValueChanged(object sender,
System.EventArgs e)
{
if (allPictures.SelectedIndex != -1)
pictureBox.Image = (Image)allPictures.SelectedValue; //this is used to
display the image in the picture box
}

System.ArgumentException: Cannot create a child list for field pictures.
at System.Windows.Forms.BindingContext.EnsureListMana ger(Object
dataSource, String dataMember)
at System.Windows.Forms.BindingContext.get_Item(Objec t dataSource, String
dataMember)
at System.Windows.Forms.ListControl.SetDataConnection (Object
newDataSource, BindingMemberInfo newDisplayMember, Boolean force)
at System.Windows.Forms.ListControl.set_ValueMember(S tring value)
at TreeViewImages.Form1.Form1_Load(Object sender, EventArgs e) in
form1.cs:line 314
what am i doing wrong.

[Dmitriy Lapshin [C# / .NET MVP]]

Hi,

First of all, try to remove the "pictures." prefix from the DisplayMember
and the ValueMember initialization values. To the best of my knowledge, the
prefix is not necessary in your databinding scenario.

--
Dmitriy Lapshin [C# / .NET MVP]
X-Unity Test Studio
http://www.x-unity.net/teststudio.aspx
Bring the power of unit testing to VS .NET IDE

"frazer" <ic***@hotmail.com> wrote in message
news:OE**************@TK2MSFTNGP09.phx.gbl...

hi i have the following code in my project

ArrayList pictures = (new Pictures()).GetAllPictures();
allPictures.DataSource = pictures;
allPictures.DisplayMember = "pictures.ToString()"; //pictures.ToString
returns the names of the pictures.
allPictures.ValueMember = "pictures.Bitmap"; //this returns the
actual picture. and i get the foll error here

private void allPictures_SelectedValueChanged(object sender,
System.EventArgs e)
{
if (allPictures.SelectedIndex != -1)
pictureBox.Image = (Image)allPictures.SelectedValue; //this is used to display the image in the picture box
}

System.ArgumentException: Cannot create a child list for field pictures.
at System.Windows.Forms.BindingContext.EnsureListMana ger(Object
dataSource, String dataMember)
at System.Windows.Forms.BindingContext.get_Item(Objec t dataSource, String dataMember)
at System.Windows.Forms.ListControl.SetDataConnection (Object
newDataSource, BindingMemberInfo newDisplayMember, Boolean force)
at System.Windows.Forms.ListControl.set_ValueMember(S tring value)
at TreeViewImages.Form1.Form1_Load(Object sender, EventArgs e) in
form1.cs:line 314
what am i doing wrong.

[Frans Bouma [C# MVP]]

"frazer" <ic***@hotmail.com> wrote in
news:OE**************@TK2MSFTNGP09.phx.gbl:

hi i have the following code in my project

ArrayList pictures = (new Pictures()).GetAllPictures();
allPictures.DataSource = pictures;
allPictures.DisplayMember = "pictures.ToString()"; //pictures.ToString
returns the names of the pictures.
You can't bind to a method, only to properties. You bind the
datasource pictures. In that datasource, objects are stored. for
DisplayMember you specify which property of THESE OBJECTS the control has
to bind to. If you picture object doesn't have a property 'Name', add it
and bind to that. Below, bind to Bitmap, not pictures.Bitmap.

FB
allPictures.ValueMember = "pictures.Bitmap"; //this returns the
actual picture. and i get the foll error here

private void allPictures_SelectedValueChanged(object sender,
System.EventArgs e)
{
if (allPictures.SelectedIndex != -1)
pictureBox.Image = (Image)allPictures.SelectedValue; //this is used
to
display the image in the picture box
}

System.ArgumentException: Cannot create a child list for field pictures.
at System.Windows.Forms.BindingContext.EnsureListMana ger(Object
dataSource, String dataMember)
at System.Windows.Forms.BindingContext.get_Item(Objec t dataSource,
String
dataMember)
at System.Windows.Forms.ListControl.SetDataConnection (Object
newDataSource, BindingMemberInfo newDisplayMember, Boolean force)
at System.Windows.Forms.ListControl.set_ValueMember(S tring value)
at TreeViewImages.Form1.Form1_Load(Object sender, EventArgs e) in
form1.cs:line 314
what am i doing wrong.

--
Get LLBLGen Pro, the new O/R mapper for .NET: http://www.llblgen.com
My .NET Blog: http://weblogs.asp.net/fbouma
Microsoft C# MVP

[frazer]

hi
that works fine.
now i want to display an image when the user clicks on combo box items.
i can do that but i have to cast it.

Picture p = (Picture)allPictures.SelectedItem;
this.pictureBox.Image = (Bitmap)(p.Bitmap);

this doesnt work.
this.pictureBox.Image = (Bitmap)allPictures.SelectedItem ;

shouldnt it cast it to a picture object automatically?
rather than me explicitly casting it?

"Frans Bouma [C# MVP]" <pe******************@xs4all.nl> wrote in message
news:Xn********************************@207.46.248 .16...

"frazer" <ic***@hotmail.com> wrote in
news:OE**************@TK2MSFTNGP09.phx.gbl:

hi i have the following code in my project

ArrayList pictures = (new Pictures()).GetAllPictures();
allPictures.DataSource = pictures;
allPictures.DisplayMember = "pictures.ToString()"; //pictures.ToString
returns the names of the pictures.

You can't bind to a method, only to properties. You bind the
datasource pictures. In that datasource, objects are stored. for
DisplayMember you specify which property of THESE OBJECTS the control has
to bind to. If you picture object doesn't have a property 'Name', add it
and bind to that. Below, bind to Bitmap, not pictures.Bitmap.

FB

allPictures.ValueMember = "pictures.Bitmap"; //this returns the
actual picture. and i get the foll error here

private void allPictures_SelectedValueChanged(object sender,
System.EventArgs e)
{
if (allPictures.SelectedIndex != -1)
pictureBox.Image = (Image)allPictures.SelectedValue; //this is used
to
display the image in the picture box
}

System.ArgumentException: Cannot create a child list for field pictures.
at System.Windows.Forms.BindingContext.EnsureListMana ger(Object
dataSource, String dataMember)
at System.Windows.Forms.BindingContext.get_Item(Objec t dataSource,
String
dataMember)
at System.Windows.Forms.ListControl.SetDataConnection (Object
newDataSource, BindingMemberInfo newDisplayMember, Boolean force)
at System.Windows.Forms.ListControl.set_ValueMember(S tring value)
at TreeViewImages.Form1.Form1_Load(Object sender, EventArgs e) in
form1.cs:line 314
what am i doing wrong.

--
Get LLBLGen Pro, the new O/R mapper for .NET: http://www.llblgen.com
My .NET Blog: http://weblogs.asp.net/fbouma
Microsoft C# MVP