Grid in a combo box [modified] - WPF Discussion Boards

Re: Client side validation

2-Aug-11 7:22

Theres already one built for you.

http://wpfconverters.codeplex.com/wikipage?title=User%20Documentation#ExpressionConverter[^]

Client side validation

yesu prakash1-Aug-11 20:14

yesu prakash

1-Aug-11 20:14

Hi,
I want to validate the controls in asp.net silverlight when click a button before save.
We need any validation controls or javascript?
i need to work same as asp.net validation control or javascript validation.

Regards,
YPKI

Mycroft Holmes4-Aug-11 13:07

Mycroft Holmes

4-Aug-11 13:07

Your question does not make sense, you are asking for information about both asp.net and silverlight, in a silverlight forum. Either you are using silverlight or not, decide and then ask a more appropriate question.

You do not use javascript to validate silverlight input, javascript works in conjunction with asp (html) not xaml.

Never underestimate the power of human stupidity
RAH

Distance Calculate Of A Route

mrhydn1-Aug-11 3:44

mrhydn

1-Aug-11 3:44

Hi... I want to distance calculate of a route with Bing Maps in Silverlight 4 (Using VB.Net- NOT C#)

I can calculate a route between two cities but I don't know how many kilometers that ROUTE...I want to learn it... That is important for me...

Grid in a combo box [modified]

Lutosław31-Jul-11 2:57

31-Jul-11 2:57

Hello again!

I have searched for it but couldn't find an apropriate solution.

I have a list of objects, and I want to arrange them in rows, but still allowing user to select any individual item. For example:

list = { a1, a2,a3,b1,b2,b3}

In a combobox I would like to see:

[   ]V
a1  a2  a3
b1  b2  b3

Items in a combobox are enumeration members and value of a combobox should be bound.
User can select any value from the list. Moreover, items a2,b2,c2,... (that is, when index%3==1) should appear in bold (extra feature).

I have tried to set a List<List<MyClass>> as a datasource, but in that case user would be able to set a whole row and not individual items. Such behaviour is unacceptable.

How to accomplish this?

Thanks in advance,

Greetings - Jacek

modified on Sunday, July 31, 2011 6:56 PM

teejayem31-Jul-11 6:42

teejayem

31-Jul-11 6:42

From MSDN[^] - A ListBoxItem is a ContentControl, which means that it can contain a single object of any type (such as a string, an image, or a panel).

This means you can directly add any type of content you wish (like a grid).

Grid grid = new Grid();
grid.Children.Add(new TextBlock { Text = "Hello"});

listBox.Items.Add(grid);

Or you can use a grid in your ItemTemplate

<ListBox x:Name="listBox" HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <Grid HorizontalAlignment="Stretch">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition />
                    <ColumnDefinition />
                    <ColumnDefinition />
                </Grid.ColumnDefinitions>

                <TextBlock Grid.Column="0" Text="{Binding Property1}" FontWeight="{Binding Path=Property1, Converter={StaticResource fontWeightConverter}}" />
                <TextBlock Grid.Column="1" Text="{Binding Property2}" FontWeight="{Binding Path=Property2, Converter={StaticResource fontWeightConverter}}" />
                <TextBlock Grid.Column="2" Text="{Binding Property3}" FontWeight="{Binding Path=Property3, Converter={StaticResource fontWeightConverter}}" />
            </Grid>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

listBox.ItemsSource = new MyClass[] {
    new MyClass { Property1 = "a1", Property2 = "a2", Property3 = "a3"},
    new MyClass { Property1 = "b1", Property2 = "b2", Property3 = "b3"},
    new MyClass { Property1 = "c1", Property2 = "c2", Property3 = "c3"},
};

and the FontWeightConverter

public class FontWeightConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        String item = value as String;
        if (item == null) return FontWeights.Normal;

        int index = int.Parse(item.Substring(1, 1));

        return index % 3 == 1 ? FontWeights.Bold : FontWeights.Normal;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Don't be overcome by evil, but overcome evil with good

Lutosław1-Aug-11 13:14

1-Aug-11 13:14

Thanks for your answer!

Unfortunately, I don't see how user could select, let say, "a3" in a grid without selecting "a1" and "a2". The list of possible values is flat, and the selection is bound to a single property. User has to choose a single item. Arranging items in a grid is a layout/GUI issue and does not reflect application logic.

Less important: let's say that ther are n columns in a grid. The solution which you have kindly provided fixes n=3. Not so bad since the number of columns will be fixed, but IMHO it is risky and not easily scalable.

Greetings - Jacek

SledgeHammer011-Aug-11 14:05

Re: Grid in a combo box [solved]

1-Aug-11 14:05

Actually, a much simpler implementation would be to just swap out the item panel for a WrapPanel. Then you could select individual items...

Simple as 1-2-3...

<ComboBox Height="23" HorizontalAlignment="Left" Margin="177,136,0,0" Name="comboBox1" VerticalAlignment="Top" Width="120">
<ComboBoxItem Content="Item 1" />
<ComboBoxItem Content="Item 2" />
<ComboBoxItem Content="Item 3" />
<ComboBoxItem Content="Item 4" />
<ComboBoxItem Content="Item 5" />
<ComboBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel />
</ItemsPanelTemplate>
</ComboBox.ItemsPanel>
</ComboBox>

Lutosław1-Aug-11 22:57

Re: Grid in a combo box [solved]

1-Aug-11 22:57

This is what I needed! Thanks very much!
You have a knowledge of the framework.

In this specific scenario, the exact solution is:

<WrapPanel ItemWidth="45" Width="225" />

which gives exactly 5 items in a row, as requested.

Greetings - Jacek

SledgeHammer012-Aug-11 7:20

Re: Grid in a combo box [solved]

2-Aug-11 7:20

You're welcome. BTW... forgot to mention the bold thing... you should use the ListBox AlternationCount for the bold feature.

Lutosław2-Aug-11 8:52

2-Aug-11 8:52

OK I will try it.

Greetings - Jacek

SledgeHammer011-Aug-11 14:05

Binding: Accept an empty string in enumeration [modified]

1-Aug-11 14:05

I'd pass on this implementation. Too much hard coding of everything.

Lutosław30-Jul-11 10:24

Re: Binding: Accept an empty string in enumeration

30-Jul-11 10:24

Hello!

I have a class:

class MyClass
{
   public enum Letters {A,B,C}
   public Letters Letter {get;set;}
   public bool IsUsed { get; set; }
   // lots of other data
}

Now, I'd like to bind the Letter property to a Textbox.Text. Works fine, but if a user left the textbox empty, then a parsing error would occur. Instead, in that case I would like to set the IsUsed property to false. I do not want to have a combo box + checkbox, because the enum values are short and well known (like letters) and writing them in a text box is most convenient.

I had tried to bind whole MyClass object and use a converter, but the ConvertBack method didn't have enough data to generate a MyClass object from scratch (there are other members than Letter and IsUsed). I had also tried to pass the original object as a converter parameter but it came out that I cannot bind to ConverterParameter so I am in a dead point.

NOTE: Everything happens in a DataTemplate sandbox for ItemsControl.ItemTemplate, like here:

<DataTemplate x:Key="DataTemplate_Level2">
    <TextBox Text="{Binding Path=Letter, Mode=TwoWay}"  Width="40" Margin="2" />
</DataTemplate>

How to get it working?

Thanks in advnace

Greetings - Jacek

modified on Saturday, July 30, 2011 4:36 PM

teejayem30-Jul-11 12:23

teejayem

30-Jul-11 12:23

Making the letter property nullable will fix your paticular issue. But, what if someone types "D"? I would personally use a Selector (like combobox) so the user can choose a valid Letter instead of guessing which letters are valid.

Don't be overcome by evil, but overcome evil with good

Re: Binding: Accept an empty string in enumeration

Lutosław31-Jul-11 1:16