Changing Column Chart Bar Width Through Code

3 replies. Latest Post by JustinAngel on December 31, 2008.

(0)

tsmccartan

Member

8 points

19 Posts

Changing Column Chart Bar Width Through Code

12-30-2008 5:32 PM |

Can you create and set a style programatically through code? Like the following:

Style ChartSeriesStyle = new Style();

ChartSeriesStyle.TargetType = typeof(ColumnDataPoint);

ChartSeriesStyle.SetValue(ColumnDataPoint.MinWidthProperty,2);

ChartSeriesStyle.SetValue(ColumnDataPoint.MaxWidthProperty, 2);

((ColumnSeries)this.MainChart.Series[0]).DataPointStyle = ChartSeriesStyle;

((ColumnSeries)this.MainChart.Series[0]).ItemsSource = chartData;

This crashes on me, so I don't think it is correct. Any help would be appreciated.

Thanks

lee_sl

Contributor

2992 points

585 Posts

Re: Changing Column Chart Bar Width Through Code

12-31-2008 2:31 AM |

try

ChartSeriesStyle.SetValue(ColumnDataPoint.MinWidthProperty,2.0);

ChartSeriesStyle.SetValue(ColumnDataPoint.MaxWidthProperty, 2.0);

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tsmccartan

Member

8 points

19 Posts

Re: Changing Column Chart Bar Width Through Code

12-31-2008 9:20 AM |

Thanks for the reply. Unfortunatly, this still causes the same error:

Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))

I have another related question. Is there a way to change the individual bars in a chart to a different color, through code? I have to highlight a specific bar, based on its values after binding.

Thanks again,

Tom

JustinAngel

Contributor

4415 points

596 Posts

Re: Changing Column Chart Bar Width Through Code

12-31-2008 3:09 PM |

Here's the XAML code needed to set the style:

        <charting:Chart x:Name="chart">
            <charting:ColumnSeries ItemsSource="{Binding}"
                                  DependentValueBinding="{Binding Value}"
                                  IndependentValueBinding="{Binding Key}">
                <charting:ColumnSeries.DataPointStyle>
                    <Style TargetType="charting:ColumnDataPoint">
                        <Setter Property="MaxWidth" Value="20" />
                    </Style>
                </charting:ColumnSeries.DataPointStyle>
            </charting:ColumnSeries>
        </charting:Chart>
 

    chart.DataContext = new KeyValuePair<string, int>[]
            {
                new KeyValuePair<string, int>("hello", 1),
                new KeyValuePair<string, int>("world", 2),
                new KeyValuePair<string, int>("foo", 3),
                new KeyValuePair<string, int>("bar", 4)
            };

If you want to specify the DataPointStyle in code you'll have to use the StylePalette on the chart.

        <charting:Chart x:Name="chart">
            <charting:ColumnSeries ItemsSource="{Binding}"
                                  DependentValueBinding="{Binding Value}"
                                  IndependentValueBinding="{Binding Key}">
            </charting:ColumnSeries>
        </charting:Chart>

        public SilverlightControl32()
        {
            InitializeComponent();
 
            System.Windows.Style DataPointStyle = new Style(typeof(ColumnDataPoint));
            DataPointStyle.Setters.Add(new Setter(ColumnDataPoint.MaxWidthProperty, 10.0));
            StylePalette palette = new StylePalette() { DataPointStyle };
            chart.StylePalette = palette;
 
            this.Loaded += new RoutedEventHandler(SilverlightControl32_Loaded);
        }
 
        void SilverlightControl32_Loaded(object sender, RoutedEventArgs e)
        {
            chart.DataContext = new KeyValuePair<string, int>[]
            {
                new KeyValuePair<string, int>("hello", 1),
                new KeyValuePair<string, int>("world", 2),
                new KeyValuePair<string, int>("foo", 3),
                new KeyValuePair<string, int>("bar", 4)
            };
        }

There seems to be a bug setting the DataPointStyle once the series has been initialized from XAML, so working through the StylePalette is your best bet.
I've opened up a Silverlight Toolkit codeplex issue to document that DataPointStyle itself is not respected when set from code:
http://www.codeplex.com/Silverlight/WorkItem/View.aspx?WorkItemId=1302
If you'd like to see this issue fixed, please feel free to vote on it.

--
Justin Angel,
Blog @ http://silverlight.net/blogs/JustinAngel
Twitter @ http://twitter.com/JustinAngel