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Conditional tooltip for DataGridTextColumn

I am currently facing a small issue with my DataGridTextColumn.
I want to display a tooltip at a DataGridTextColumn but only if the text is not empty.
How can I achieve this? The code that I am currently using:
<DataGridTextColumn IsReadOnly="True" Header="Person" Binding="{Binding SomeBinding, TargetNullValue='-'}" Width="Auto"
CellStyle="{StaticResource SomeStyle}"/>
With the style
<Style x:Key="SomeStyle"
TargetType="DataGridCell" BasedOn="{StaticResource InactiveStyle}">
<Style.Setters>
<Setter Property="ToolTip" Value="{Binding Path=SomeBinding}"/>
</Style.Setters>
</Style>
This code does provide me the tooltip, however, it is also showing the tooltip when there is no text. If there are any questions, please let me know and I can help you.

Try to add data triggers for string.Empty and null:
<Style x:Key="SomeStyle" TargetType="DataGridCell"
BasedOn="{StaticResource InactiveStyle}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=SomeBinding}" Value="">
<Setter Property="ToolTip" Value="{x:Null}"/>
</DataTrigger>
<DataTrigger Binding="{Binding Path=SomeBinding}" Value="{x:Null}">
<Setter Property="ToolTip" Value="{x:Null}"/>
</DataTrigger>
</Style.Triggers>
<Style.Setters>
<Setter Property="ToolTip" Value="{Binding Path=SomeBinding}"/>
</Style.Setters>
</Style>

Here is an approach :
//Create a class which inherits from IValueConverter
public class CellToolTipConverter : IValueConverter
{
#region IValueConverter Membres
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
string stringValue = (string)value;
if (!string.IsNullOrEmpty(stringValue))
return "Your tooltip";//As you are in a c# class, you have many possibilities.
else
return string.Empty;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
#endregion
}
//In your xaml :
//Declare your namespace
xmlns:CustomClasses="clr-namespace:YourAssamblyName.YourNameSpaceOfConverterClass"
<UserControl.Resources>
<CustomClasses:CellToolTipConverter x:Key="CustomToolTipConverter"/>
</UserControl.Resources>
//In your grid view
<GridView.RowStyle>
<Style TargetType="{x:Type telerik:GridViewRow}">
<Setter Property="MyCustomToolTipProperty" Value="{Binding YourProperty, Converter=
{StaticResource CustomToolTipConverter}}"/>
</Style>
</GridView.RowStyle>

PropertyChangedEventHandler is null even property is change

I have a data grid and one main checkbox. When I check changed in the main checkbox, this will affect all checkbox that inside data grid; I just do it programmatically.
My so-called ViewModel:
foreach (TimeSheetModel value in TimeSheetList.Intersect(selectedlist))
{
if (!chkmain.IsChecked.GetValueOrDefault())
{
value.IsApproved = false;
}
else
{
value.IsApproved = true;
}
}
This is my TimeSheetModel:
public class TimeSheetModel:BaseModel, ICloneable
{
bool _IsApproved;
public bool IsApproved
{
get
{
return _IsApproved;
}
set
{
if (_IsApproved != value)
{
_IsApproved = value;
RaisePropertyChange("IsApproved");
}
}
}
}
This is my BaseModel:
public class BaseModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public void RaisePropertyChange(string prop)
{
try
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(prop));
IsUpdated=true
}
}
catch (Exception ex)
{
throw ex;
}
}
}
This is my xaml:
<DataGridTemplateColumn Visibility="{Binding IsShowApprove,Source={x:Static c:TMSHelper.Current}}">
<DataGridTemplateColumn.HeaderTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical"
HorizontalAlignment="Right"
Margin="-8">
<TextBlock Text="Approve"
Height="20"
Margin="5,3,0,0" />
<CheckBox Margin="27,0,0,0"
x:Name="chkMainApproved"
Checked="chkApproved_Checked"
Unchecked="chkApproved_Checked">
</CheckBox>
</StackPanel>
</DataTemplate>
</DataGridTemplateColumn.HeaderTemplate>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<CheckBox BorderThickness="1"
Margin="27,0,0,0"
Background="{Binding RelativeSource={RelativeSource AncestorType={x:Type DataGridRow}},Path=Background}"
IsChecked="{Binding IsApproved,UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}"
KeyDown="DatePicker_KeyDown"
>
<CheckBox.Style>
<Style TargetType="CheckBox" BasedOn="{StaticResource MetroCheckBox}">
<Setter Property="IsEnabled"
Value="True" />
<Style.Triggers>
<DataTrigger Binding="{Binding IsLock}" Value="True">
<Setter Property="IsEnabled" Value="False"/>
</DataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsLock}"
Value="True" />
</MultiDataTrigger.Conditions>
<Setter Property="IsEnabled"
Value="False" />
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsNew}"
Value="True" />
<Condition Binding="{Binding CanAdd}"
Value="False" />
</MultiDataTrigger.Conditions>
<Setter Property="IsEnabled"
Value="False" />
</MultiDataTrigger>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding IsNew}"
Value="False" />
<Condition Binding="{Binding CanEdit}"
Value="False" />
</MultiDataTrigger.Conditions>
<Setter Property="IsEnabled"
Value="False" />
</MultiDataTrigger>
</Style.Triggers>
</Style>
</CheckBox.Style>
</CheckBox>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
According to my understanding, if I change the value.IsApproved=true (inside ViewModel) this will raise the IsApproved property inside TimeSheetModel and go to RaisePropertyChanged method and go to PropertyChanged and IsUpdated property will be true.
My problem is My propertyChanged is sometimes null, sometimes has value. Even if IsApproved value was changed.
This is not happening in all checkbox.
Hope you will understand my question and pls let me know anything I can provide.

WPF, setting background color with trigger

I have a customcontrol which render a textbox. I've also a style that set the color of the background based on some conditions as follows:
<Style x:Key="ArtParamStyle" TargetType="av:DC_Base">
<Setter Property="Background" Value="{StaticResource EditableAreaBrush}" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=Info.Upd.IsAutoCalc}" Value="True">
<Setter Property="Background" Value="Red" />
</DataTrigger>
<DataTrigger Binding="{Binding Path=Forced}" Value="True">
<Setter Property="Background" Value="LightGreen" />
</DataTrigger>
</Style.Triggers>
</Style>
Initially as the value of my textbox is autocalculated, the background is correctly red. If I also set the Forced as true (by ticking a chebckbox) I've a weird result, the border of textbox is lightgreen but background not.
It seems to be a strange color, a combination of red and lightgreen. As test, if I set the "IsAutoCalc" color as Transparent, the trigger works correctly. How can I solve this?

your code seems to be correct. But I provide you my sample:
XAML:
<Window.Resources>
<Style x:Key="ArtParamStyle" TargetType="TextBox">
<Setter Property="Background" Value="Yellow" />
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition Binding="{Binding Bool1}" Value="True"/>
<Condition Binding="{Binding Bool2}" Value="False"/>
</MultiDataTrigger.Conditions>
<Setter Property="Background" Value="Red" />
<Setter Property="BorderBrush" Value="Red" />
</MultiDataTrigger>
<DataTrigger Binding="{Binding Bool2}" Value="True">
<Setter Property="Background" Value="LightGreen" />
<Setter Property="BorderBrush" Value="LightGreen" />
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<StackPanel>
<TextBox Style="{StaticResource ArtParamStyle}" Height="50" Margin="4"/>
<CheckBox IsChecked="{Binding Bool1}"/>
<CheckBox IsChecked="{Binding Bool2}"/>
</StackPanel>
</Grid>
In this case I used Multidatatrigger to set red background when Bool2(your forced) is not checked.
MainWindow.cs:
public partial class MainWindow : Window, INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private void RaisePropertyChaged(string property)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(property));
}
}
private bool bool1;
public bool Bool1
{
get { return bool1; }
set { bool1 = value; RaisePropertyChaged("Bool1"); }
}
private bool bool2;
public bool Bool2
{
get { return bool2; }
set { bool2 = value; RaisePropertyChaged("Bool2"); }
}
public MainWindow()
{
InitializeComponent();
this.DataContext = this;
}
}
Probably your problem is related to your custom control.

WPF ListView Object DataTrigger

I'm trying to style a rectangle inside of a listview item, based on a data-field of the listview item object.
To return a boolean I'm converting the integer from daydata.workload to a boolean uasing a IValueConverter.
I'm getting no exception, the rectangle is just not affected by the DataTrigger. The other style rules are working fine.
<Window.Resources>
<cv:numConverter x:Key="capacityConverter" />
<Window.Resources>
-
<ListView Name="weekView" ItemsSource="{Binding dayList}" ItemTemplate="{StaticResource DefaultTemplate}" >
<ListView.Resources>
<Style TargetType="Rectangle" x:Key="capacityBG">
<Setter Property="Stroke" Value="#FFE2E2E2" />
<Setter Property="Width" Value="180" />
<Setter Property="Height" Value="10" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=dayList.workload, Converter={StaticResource capacityConverter}, ConverterParameter=12}">
<DataTrigger.Value>true</DataTrigger.Value>
<Setter Property="Fill" Value="Red"/>
</DataTrigger>
</Style.Triggers>
</Style>
</ListView.Resources>
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel Orientation="Horizontal"></StackPanel>
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.ItemContainerStyle>
<Style TargetType="{x:Type ListViewItem}">
<Setter Property="Background" Value="Transparent" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListViewItem}">
<ContentPresenter />
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListView.ItemContainerStyle>
</ListView>
-
<Rectangle Style="{DynamicResource capacityBG}" VerticalAlignment="Top" Grid.Row="0" />
-
public class numConverter : IValueConverter
{
object IValueConverter.Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return ((int)value) > val;
}
object IValueConverter.ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
public int val { get; set; }
}
-
public class dayData
{
public DateTime date { get; set; }
public int workload { get; set; }
public List<job> jobs { get; set; }
}

The problem here is that values entered for the converter parameter and the data trigger value are treated as string. You need to specify the type for each one of these values like shown below:
xmlns:sys="clr-namespace:System;assembly=mscorlib"
<Style.Triggers>
<DataTrigger>
<DataTrigger.Binding>
<Binding Path="WorkLoad" Converter="{StaticResource capacityConverter}">
<Binding.ConverterParameter>
<sys:Int32>12</sys:Int32>
</Binding.ConverterParameter>
</Binding>
</DataTrigger.Binding>
<DataTrigger.Value>
<sys:Boolean>true</sys:Boolean>
</DataTrigger.Value>
<Setter Property="Fill" Value="Red"/>
</DataTrigger>
</Style.Triggers>
Then you can cast converter parameter to an int to make the comparison.
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return (int)value > (int)parameter;
}

wpf how to bind to DataContext existence?

I set the datacontext dynamically in code. I would like a button on screen to be enabled/disabled depending if DataContext == null or not. I can do it in code when I assign the DataContext but it would be better if I can bind like that :)

You should be able to use a DataTrigger on the button style to disable your button when the DataContext is null. The other option is to bind the IsEnabled property to the DataContext and use a value converter to return false if DataContext is null and true otherwise.
With trigger:
<Button>
<Button.Style>
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=DataContext, RelativeSource={RelativeSource Self}}" Value="{x:Null}">
<Setter Property="IsEnabled" Value="false"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
With converter:
Converter:
public class DataContextSetConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return value != null;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
And use it
<UserControl.Resources>
<local:DataContextSetConverter x:Key="dataContextSetConverter"/>
</UserControl.Resources>
...
<Button IsEnabled="{Binding Path=DataContext, RelativeSource={RelativeSource Self}, Converter={StaticResource dataContextSetConverter}}"/>

This should do it:
<Button Content="ButtonName">
<Button.Style>
<Style TargetType="{x:Type Button}">
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=DataContext}" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed" />
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>