I am binding a datagrid to a BindingList of TransectPoint objects (it doesn't matter what a TransectPoint is for this question).

One of the properties of a TransectPoint is AverageSenescentCrownRadiusProperty (code is below). Note in particular that the value of the property must be > 0 (or null) - as enforced by DoubleIsPositive.

When editing data in the grid, it will work (almost) perfectly - if I enter a negative value (eg -5) in the column related to this property then the background of the cell will go red. If I hover over the cell it shows this tooltip:

 '-5' is not a valid value for property 'AverageSenescentCrownRadiusProperty'.

Is there a way to customise the message that is displayed (since I would rather the user not see 'AverageSenescentCrownRadiusProperty')?

CODE IS BELOW

public static readonly DependencyProperty AverageSenescentCrownRadiusProperty = DependencyProperty.Register("AverageSenescentCrownRadius", typeof(double?), typeof(TransectPoint), new PropertyMetadata(new double?(0f)), new ValidateValueCallback(DoubleIsPositive));

[XmlElement("AverageSenescentCrownRadius")]

public double? AverageSenescentCrownRadius

{

get { return (double?)GetValue(AverageSenescentCrownRadiusProperty); }

set { SetValue(AverageSenescentCrownRadiusProperty, value); }

}

private static bool DoubleIsPositive(object value)

{

double? tempDouble = (double?) value;

if (tempDouble.HasValue)

return tempDouble >= 0;

else

return true;

}

You could use ValidationRules as described in the Validating Data topic. The upcoming version of the grid will provide enhanced validation features, including support for IDataErrorInfo.

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Technical Writer - Xceed Software

Of all the things I've lost, I miss my mind the most. - Mark Twain

Thanks for the heads up - I will check that article out.

 

BTW, I think there is a typo in that document:

 (i.e., a row exists edit mode).

should be:

 (i.e., a row exits edit mode).

I solved the issue as follows. Note that it didn't require me to use a CellValidationRule (so I can keep my validation in the object model where I would rather it be than in the UI).

Note in particular the way I am setting the ToolTip...

 

<Style x:Key="cell_error" TargetType="{x:Type xcdg:DataCell}">

<Setter Property="Foreground" Value="Red"/>

<Setter Property="ToolTip" Value="Invalid value"/>

</Style>

 

<xcdg:Column FieldName="AverageSenescentCrownRadius"

Title="r (Senescent)"

CellErrorStyle="{StaticResource cell_error}"

Width="72">

</xcdg:Column>