I solved in on my own. Just changed the controls in the cells every time i check the checkbox.

 <ig:ColumnLayout.Columns>
<ig:TextColumn Key="AttributeModel.Attribute" HeaderText="{Binding ArticleAttributeList_XamGridTextColumn_Attribute_HeaderText, Source={StaticResource Localization}}" />
<ig:TextColumn Key="AttributeModel.Measure" HeaderText="{Binding ArticleAttributeList_XamGridTextColumn_Measure_HeaderText, Source={StaticResource Localization}}" />
<ig:TextColumn Key="AttributeModel.Value" HeaderText="{Binding ArticleAttributeList_XamGridTextColumn_Value_HeaderText, Source={StaticResource Localization}}" />
<ig:TemplateColumn Key="Status" HeaderText="{Binding ArticleAttributeList_XamGridTextColumn_Status_HeaderText, Source={StaticResource Localization}}">
<ig:TemplateColumn.ItemTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding Status}" Checked="Status_Checked" Unchecked="Status_Unchecked" />
</DataTemplate>
</ig:TemplateColumn.ItemTemplate>
</ig:TemplateColumn>
</ig:ColumnLayout.Columns>

private void Status_Checked(object sender, RoutedEventArgs e)
{
if (articleList.ActiveCell == null) return;
if (articleList.ActiveCell.Control == null) return;
if (articleList.ActiveCell.Control.Content == null) return;
if (articleList.ActiveCell.Control.Content as CheckBox != sender as CheckBox) return;
if (articleList.ActiveCell.Row == null) return;
if (articleList.ActiveCell.Row.Cells == null) return;
if (articleList.ActiveCell.Row.Cells.Count < 4) return;

TextBlock textBlock = new TextBlock();
Binding binding = new Binding("AttributeModel.Value");
textBlock.SetBinding(TextBlock.TextProperty, binding);

articleList.ActiveCell.Row.Cells[2].Control.Content = textBlock;

}

Like i said while in editing mode i can't do anything except editing the cell. But i would like to change other data AND hold the cell in editing mode until i check the box.

my shortened xaml

<ig:XamGrid ItemsSource="{Binding ArticleAttributeModels, UpdateSourceTrigger=Default}" 
AutoGenerateColumns="False" x:FieldModifier="private" Name="articleList"  CellExitingEditMode="articleList_CellExitingEditMode">
<ig:XamGrid.Columns>
  <TextColumns ...>
  <ig:ColumnLayout Key="Attributes" AutoGenerateColumns="False">
<ig:ColumnLayout.Columns>
  <ig:TemplateColumn Key="AttributeModel.Attribute" >
<ig:TemplateColumn.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding AttributeModel.Attribute}" />
</DataTemplate>
</ig:TemplateColumn.ItemTemplate>
</ig:TemplateColumn>
  <ig:TemplateColumn Key="AttributeModel.Measure" >
<ig:TemplateColumn.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding AttributeModel.Measure}" />
</DataTemplate>
</ig:TemplateColumn.ItemTemplate>
</ig:TemplateColumn>
  <ig:TemplateColumn Key="AttributeModel.Value" >
<ig:TemplateColumn.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding AttributeModel.Value}" />
</DataTemplate>
</ig:TemplateColumn.ItemTemplate>
<ig:TemplateColumn.EditorTemplate>
<DataTemplate>
<Editors:XamComboEditor IsEditable="True" ItemsSource="{Binding SuggestedValues}" />
</DataTemplate>
</ig:TemplateColumn.EditorTemplate>
</ig:TemplateColumn>
  <ig:TemplateColumn Key="Status" >
<ig:TemplateColumn.ItemTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding Status}" Checked="Status_Checked" Unchecked="Status_Unchecked"/>
</DataTemplate>
</ig:TemplateColumn.ItemTemplate>
<ig:TemplateColumn.EditorTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="Score:" />
<TextBlock Text="{Binding Score}" Margin="3,0" />
<CheckBox IsChecked="{Binding Status}" Checked="Status_Checked" Unchecked="Status_Unchecked"/>
</StackPanel>
</DataTemplate>
</ig:TemplateColumn.EditorTemplate>
</ig:TemplateColumn>
</ig:ColumnLayout.Columns>
<ig:ColumnLayout.EditingSettings>
  <ig:EditingSettingsOverride AllowEditing="Cell" />
  </ig:ColumnLayout.EditingSettings>

my shortened c# code

private void Status_Checked(object sender, RoutedEventArgs e)
{
  articleList.ExitEditMode(true);
}

private void Status_Unchecked(object sender, RoutedEventArgs e)
   {
articleList.EnterEditMode(articleList.ActiveCell.Row.Cells[2]);

}

private void articleList_CellExitingEditMode(object sender, ExitEditingCellEventArgs e)
{
if (e.Cell.Column.Key == "AttributeModel.Value")
{
e.Cancel = (bool)e.Cell.Row.Cells[3].Value;
}
}

In a perfect world my xamgrid should change the look of the cell with the key "Status" and should make the cell with the key "Value" editable / not editable if the user presses the checkbox.