Calculated Column using MVVM

[Koren]

I have two columns in my grid that are calculated using other columns.  Because I need the totals for my database update, I decided to do the calculations in my view model and set the property as changed when these values are updated.  This works perfectly in edit mode.  If I modify my price, the new value gets updated and displays in the grid correctly.  However, I am getting different results for a new record.  If I leave the value column as read only, the display never gets updated even though the value field in my view model is correctly updated.  If I take off the read only setting on the value column, the display does update but only if I give that column focus.  I don't have to do this in Edit mode so I am not sure how to fix this for insert mode.

thanks!

[Maya]

Hi Koren,

In order to provide you with an appropriate solution, I would need a bit more details. How do you calculate the values in the last column ? Do you use a GridViewExpressionColumn or do you follow an approach similar to this one ? May you verify if the CellEditEnded event is fired when filling up the values in the new item ? It would be great if you share any relevant code-snippets or send us a sample project simulating the issue.
 

All the best,
Maya
the Telerik team

[Koren]

I tried the GridViewExpressionColumn but had the same problem on an insert.  I also need the value to update the database so I decided to just use my view model.  Edit works great but the Insert does not show the updated value.
thx, Koren

Here is the relevant parts of the view model:

 

        private void UpdateValue()
        {
            this.Value = this.Acres * this.YieldPerAcre * this.UnitPrice;
        }
       public double Acres
        {
            get { return _cropProductionRecord.Acres; }
            set
            {
                _cropProductionRecord.Acres = value;
                OnPropertyChanged("Acres");
                UpdateValue();
            }
        }
        public double YieldPerAcre
        {
            get { return _cropProductionRecord.YieldPerAcre; }
            set
            {
                _cropProductionRecord.YieldPerAcre = value;
                OnPropertyChanged("YieldPerAcre");
                UpdateValue();
            }
        }

        public double UnitPrice
        {
            get { return _cropProductionRecord.UnitPrice; }
            set
            {
                _cropProductionRecord.UnitPrice = value;
                OnPropertyChanged("UnitPrice");
                UpdateValue();
            }
        }
        public double Value
        {
            get { return _cropProductionRecord.Value; }
            set
            {
                _cropProductionRecord.Value = value;
                OnPropertyChanged("Value");
            }
        }

And the grid:
        <telerik:RadGridView DockPanel.Dock="Top" x:Name="grdCropProduction" ItemsSource="{Binding CropProductionRecords}" AutoGenerateColumns="False"
                                         IsFilteringAllowed="True" ShowGroupPanel="False" SelectionMode="Extended" ShowInsertRow="True"
                                         ActionOnLostFocus="None"  CanUserInsertRows="True" CanUserDeleteRows="True" CanUserReorderColumns="False"
                                         IsReadOnly="False" CanUserFreezeColumns="False" CanUserResizeColumns="False"
                                         Deleting="grdCropProduction_Deleting" RowIndicatorVisibility="Collapsed"
                                         RowEditEnded="grdCropProduction_RowEditEnded"
                                         AddingNewDataItem="grdCropProduction_AddingNewDataItem">
            <telerik:RadGridView.Columns>
                <telerik:GridViewColumn>
                    <telerik:GridViewColumn.CellTemplate>
                        <DataTemplate>
                            <telerik:RadButton Content="Delete" Command="telerikGrid:RadGridViewCommands.Delete" CommandParameter="{Binding}" />
                        </DataTemplate>
                    </telerik:GridViewColumn.CellTemplate>
                </telerik:GridViewColumn>
                <telerik:GridViewComboBoxColumn UniqueName="TransactionCode" Header="ATIGD" IsComboBoxEditable="True"
                                                DataMemberBinding="{Binding TransactionCodeID}"
                                                DisplayMemberPath="CodeDescription"
                                                SelectedValueMemberPath="TransactionCodeID"
                                                >
                    <telerik:GridViewComboBoxColumn.EditorStyle>
                        <Style TargetType="telerik:RadComboBox">
                            <Setter Property="OpenDropDownOnFocus" Value="true" />
                        </Style>
                    </telerik:GridViewComboBoxColumn.EditorStyle>
                </telerik:GridViewComboBoxColumn>

                <telerik:GridViewComboBoxColumn Header="Ent #" IsComboBoxEditable="True"
                                                DataMemberBinding="{Binding FarmYearEnterpriseID}"
                                                DisplayMemberPath="CodeDescription"
                                                SelectedValueMemberPath="FarmYearEnterpriseID"
                                                ItemsSource="{Binding FarmYearEnterprises}">
                    <telerik:GridViewComboBoxColumn.EditorStyle>
                        <Style TargetType="telerik:RadComboBox">
                            <Setter Property="OpenDropDownOnFocus" Value="true" />
                        </Style>
                    </telerik:GridViewComboBoxColumn.EditorStyle>
                </telerik:GridViewComboBoxColumn>

                <telerik:GridViewDataColumn Header="O/R" DataMemberBinding="{Binding Owned}">
                    <telerik:GridViewDataColumn.CellTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Owned, Converter={StaticResource BooleanConverter}, ConverterParameter=OWNED}" />
                        </DataTemplate>
                    </telerik:GridViewDataColumn.CellTemplate>
                </telerik:GridViewDataColumn>
                <telerik:GridViewDataColumn Header="Opr %" DataMemberBinding="{Binding OperatorPercent}" DataFormatString="{}{0:p}" IsFilterable="False" />
                <telerik:GridViewDataColumn Header="Acres" Width="60" DataMemberBinding="{Binding Acres}" IsFilterable="False" />
                <telerik:GridViewDataColumn Width="60" DataMemberBinding="{Binding YieldPerAcre}" IsFilterable="False">
                    <telerik:GridViewDataColumn.Header>
                        <TextBlock Text="Yield Per Acre" TextWrapping="Wrap" />
                    </telerik:GridViewDataColumn.Header>
                </telerik:GridViewDataColumn>
                <!--<telerik:GridViewDataColumn Header="QuantityCodeID" DataMemberBinding="{Binding QuantityCodeID}" IsFilterable="False" />-->
                <telerik:GridViewDataColumn Width="60" DataMemberBinding="{Binding UnitPrice}" DataFormatString="{}{0:c}" IsFilterable="False">
                    <telerik:GridViewDataColumn.Header>
                        <TextBlock Text="Unit Price" TextWrapping="Wrap" />
                    </telerik:GridViewDataColumn.Header>
                </telerik:GridViewDataColumn>
                <!--<telerik:GridViewExpressionColumn Header="$ Value" UniqueName="TotalValue" DataFormatString="{}{0:c}"  />-->
                <telerik:GridViewDataColumn Header="$ Value" Width="60" DataMemberBinding="{Binding Value}" DataFormatString="{}{0:c}" IsFilterable="False" IsReadOnly="True" />
                <telerik:GridViewDataColumn Width="60" DataMemberBinding="{Binding UnitWeight}" IsFilterable="False">
                    <telerik:GridViewDataColumn.Header>
                        <TextBlock Text="Unit Weight" TextWrapping="Wrap" />
                    </telerik:GridViewDataColumn.Header>
                </telerik:GridViewDataColumn>
                <telerik:GridViewDataColumn Header="Tot Units" Width="60" DataMemberBinding="{Binding TotalUnits}" IsFilterable="False" />
                <!--<telerik:GridViewExpressionColumn Header="Weight" UniqueName="TotalWeight" />-->
                <telerik:GridViewDataColumn Header="Weight" Width="60" DataMemberBinding="{Binding Weight}" IsFilterable="False" IsReadOnly="True" />
            </telerik:RadGridView.Columns>
        </telerik:RadGridView>

 

 

 

 

 

 

 

 

 

 

 

 

[Maya]

Hi Koren,

Based on the code-snippets provided, I prepared a small application in an attempt to reproduce your scenario. However, I am not able to get the behavior you specified. May you take a look at my application and let me know in case of any discrepancies according to your requirements ? Feel free to change the sample in the way you want and send it back if necessary.
 

All the best,
Maya
the Telerik team

[Koren]

I just went from a trial version to the latest version and it fixed the problem.  Must have been an issue in the last version.  thanks for the help!