Logarithm Base at Runtime / MVVM

[Courouble Damien]

Hi Guys,

i'm binding the LogarithmBase and the isLogarithm on the Axis Y
Everything looks okay, but i need to change this option at runtime by the help of a checkbox for enable / disable the log and a combobox for changing the base.
At runtime changing the base or the isLog option doesn't refresh update the chart as it suppose to be.

i found that changing the value of the isInverse refresh correctly the chart, so as a workaround i just set IsInverse twice to the inverse of himself ( so the value remain the same but looks change)

I'm okay with this workaround but that would be aweseome if it could works without that !!

here's my code, that may help you

Thanks,

Damien

''' <summary>
       ''' Get or set a boolean indicating if the YAxis is log or not
       ''' </summary>
       ''' <value></value>
       ''' <returns></returns>
       ''' <remarks></remarks>
       Public Property YAxisIsLogarithmic() As Boolean
           Get
               Return _YAxisIsLogarithmic
           End Get
           Set(ByVal value As Boolean)
               If Not Boolean.Equals(_YAxisIsLogarithmic, value) Then
                   _YAxisIsLogarithmic = value
                   Properties.SetElementValue("YAxisIsLogarithmic", value.ToString())
                   RaisePropertyChanged("YAxisIsLogarithmic")
                   ' Work around for log bug we need to change the value of the inverse and then put the value back
                   YAxisIsInverse = Not YAxisIsInverse
                   YAxisIsInverse = Not YAxisIsInverse
               End If
           End Set
       End Property

       ''' <summary>
       ''' Get or set the log base for YAxis
       ''' </summary>
       ''' <value></value>
       ''' <returns></returns>
       ''' <remarks></remarks>
       Public Property YAxisLogarithmBase() As Integer
           Get
               Return _YAxisLogarithmBase
           End Get
           Set(ByVal value As Integer)
               If Not Integer.Equals(_YAxisLogarithmBase, value) Then
                   _YAxisLogarithmBase = value
                   Properties.SetElementValue("YAxisLogarithmBase", value.ToString())
                   RaisePropertyChanged("YAxisLogarithmBase")
                   ' Work around for log bug we need to change the value of the inverse and then put the value back
                   YAxisIsInverse = Not YAxisIsInverse
                   YAxisIsInverse = Not YAxisIsInverse

               End If
           End Set
       End Property

''' <summary>
       ''' Get or set a boolean value indicating if the Axis is inverse or not
       ''' </summary>
       ''' <value></value>
       ''' <returns></returns>
       ''' <remarks></remarks>
       Public Property YAxisIsInverse() As Boolean
           Get
               Return _YAxisIsInverse
           End Get
           Set(ByVal value As Boolean)
               If Not Boolean.Equals(_YAxisIsInverse, value) Then
                   _YAxisIsInverse = value
                   Properties.SetElementValue("YAxisIsInverse", value.ToString())
                   RaisePropertyChanged("YAxisIsInverse")
               End If
           End Set
       End Property

And the XAML As Well ..

<!-- Y Axis -->

                        <telerik:ChartArea.AxisY>

                            <telerik:AxisY Title="{Binding YAxisTitle}"

                                           IsInverse="{Binding YAxisIsInverse}"

                                           AutoRange="{Binding YAxisIsAutoRange}"

                                           IsZeroBased="{Binding YAxisIsZeroBased}"

                                           IsLogarithmic="{Binding YAxisIsLogarithmic}"

                                           LogarithmBase="{Binding YAxisLogarithmBase}"

                                           MinValue="{Binding YAxisMinValue}"

                                           MaxValue="{Binding YAxisMaxValue}"

                                           Step="{Binding YAxisStep}"

                                           AxisLabelsVisibility="{Binding YAxisLabelsVisible, Converter={StaticResource BooleanToVisibilityConverter}}"   

                                           LabelRotationAngle="{Binding YAxisLabelsRotation}"

                                           MinorGridLinesVisibility="{Binding YAxisMinorGridLinesVisible, Converter={StaticResource BooleanToVisibilityConverter}}"

                                           MajorGridLinesVisibility="{Binding YAxisMajorGridLinesVisible, Converter={StaticResource BooleanToVisibilityConverter}}"

                                           StripLinesVisibility="{Binding YAxisStripLinesVisible, Converter={StaticResource BooleanToVisibilityConverter}}"

                                           DefaultLabelFormat="{Binding YAxisLabelsFormat}"/>

                      </telerik:ChartArea.AxisY>


[Ves]

Hello,

Thanks for the details. The problem appears only when Authoring is set to false, so you may want to limit the workaround to be applied only in this case.

You can find the issue logged here. I have updated your Telerik points for bringing this to our attention.

Best regards,
Ves
the Telerik team

[Courouble Damien]

Thanks for tracking this issue.
But I'm sorry what's Authoring ?? Is it AutoRange / Auto Scale ? 

Thanks

Damien

[Ves]

Hi,

I am sorry about that -- I must have clicked the wrong option in the spellchecker. Indeed, it should read:

...when AutoRange is set to false...


Best regards,
Ves
the Telerik team

[AndreasW]

Hi,
I am struggling with the same issue, but in my case setting AutoRange to True does not fix the issue. Any fix for this yet?


In my case the  Chart.AxisY are bound to a bool in the ViewModel controlled by a Checkbox.
When the axis are changed for the first time from logarithmic to linear it works as expected, but when when trying to change back to logarithmic the AxisY values remains unchanged and every graph line are drawn with Yvalue = 0.

I have treid both Rebind() and the workaround with IsInversed() without luck.

XAML for my chart

<telerik:RadChart x:Name="Chart" Height="550" ItemsSource="{Binding CM}" UseDefaultLayout="True">
   <telerik:RadChart.SeriesMappings>
       <telerik:SeriesMapping LegendLabel="Item" ChartAreaName="AreaNavn" >
          <telerik:SeriesMapping.SeriesDefinition>
               <telerik:LineSeriesDefinition Visibility="{Binding IsVisible, Source={StaticResource VM}}"  ShowItemLabels="True"/>
            </telerik:SeriesMapping.SeriesDefinition>
                    <telerik:ItemMapping FieldName="Item" DataPointMember="YValue"/>
                    <telerik:ItemMapping FieldName="Year" DataPointMember="XValue"/>
             </telerik:SeriesMapping>
               <telerik:RadChart.DefaultView>
                    <telerik:ChartDefaultView ChartLegendPosition="Right">
                          <telerik:ChartDefaultView.ChartArea>
                           <telerik:ChartArea LegendName="chartLegend">
                               <telerik:ChartArea.AxisX>
                                 <telerik:AxisX

                                MajorTicksVisibility="Collapsed"
                                AutoRange="False"
                                MinorGridLinesVisibility="Visible"
                                MaxValue="{Binding SelectionEnd, ElementName=DateSlider}"
                                MinValue="{Binding SelectionStart, ElementName=DateSlider}"
                                IsDateTime="False"
                                DefaultLabelFormat="#VAL{}"
                                LabelRotationAngle="45"

                                                           />
                               </telerik:ChartArea.AxisX>
                                <telerik:ChartArea.AxisY>
                                        <telerik:AxisY
                                          x:Name="AxisY"
                                          IsLogarithmic="{Binding IsLog, Source={StaticResource MalingerVM}}"
                                          LogarithmBase="10"
                                          MajorTicksVisibility="Collapsed"
                                          AutoRange="True"
                                          ExtendDirection="None"
                                                                        />
                                            </telerik:ChartArea.AxisY>
                                                            </telerik:ChartArea>
                                    </telerik:ChartDefaultView.ChartArea>
                                    <telerik:ChartDefaultView.ChartLegend>
                                         <telerik:ChartLegend
                                             UseAutoGeneratedItems="True"
                                              Header="Items"
                                              x:Name="chartLegend"
                                              Width="150"
                                              LegendItemStyle="{StaticResource CustomLegendItemStyle}" LegendItemMarkerShape="Square"/>
                                    </telerik:ChartDefaultView.ChartLegend>
                                </telerik:ChartDefaultView>
                            </telerik:RadChart.DefaultView>
                            </telerik:RadChart>

        


Any idea how I can fix this issue?

[Ves]

Hi Andreas,

Please, find attached a small example, based on your markup and with AutoRange=true,  which works correctly for me.

Best regards,
Ves
the Telerik team

[AndreasW]

I found the problem. My datas contained zero values, wich do not go to well with log scale.




Greeting
Andreas