DataGrid Value Change before update - WPF C# MVVM-CodePudding

I'm trying to create CRUD using WPF C# MVVM. I have Document Type Master with script like below:

my XAML:

<TextBox Grid.Column="1"
                         materialDesign:HintAssist.FloatingOffset="0, -18"
                         IsReadOnly="False"
                         Style="{StaticResource MaterialDesignFloatingHintTextBox}"
                         materialDesign:HintAssist.Hint="Document Type"
                         HorizontalAlignment="Stretch"
                         FontSize="14"
                         Margin="0 10 0 20"
                         Text="{Binding Path=CurrentDocumentType.DocumentTypeName}" />

                <DataGrid x:Name="dgDocumentType"
                          CanUserAddRows="False"
                          SelectionUnit="FullRow"
                          SelectionMode="Extended"
                          AutoGenerateColumns="False"
                          IsReadOnly="True"
                          ItemsSource="{Binding Path=DocumentTypesList, Mode=TwoWay}"
                          SelectedItem="{Binding Path=SelectedDocumentType, Mode=TwoWay}">
                    <DataGrid.RowStyle>
                        <Style TargetType="{x:Type DataGridRow}">
                            <Setter Property="Foreground"
                                    Value="Black" />

                        </Style>
                    </DataGrid.RowStyle>

                    <DataGrid.Columns>
                        <DataGridTextColumn Header="ID"
                                            Binding="{Binding Path=IdDocumentType, Mode=TwoWay}"
                                            Visibility="Hidden" />
                        <DataGridTextColumn Header="Document Type"
                                            Binding="{Binding Path=DocumentTypeName, Mode=TwoWay}" />
                    </DataGrid.Columns>

                </DataGrid>

And this is my ViewModel:

 private DocumentType selectedDocumentType;

    public DocumentType SelectedDocumentType
    {
        get { return selectedDocumentType; }
        set
        {
            selectedDocumentType = value;
            CurrentDocumentType = selectedDocumentType;

            OnPropertyChanged("SelectedDocumentType");
            
        }
    }

    private DocumentType currentDocumentType;

    public DocumentType CurrentDocumentType
    {
        get { return currentDocumentType; }
        set
        {
            currentDocumentType = value;
            OnPropertyChanged("CurrentDocumentType");


        }
    }

i'm using CurrentDocumentType = selectedDocumentType; so my textbox always show selected value everytime row in datagrid selected.

The problem is everytime i try to change value in textbox currentDocument Type, selected item in datagrid changes too. i want value in datagrid change when i hit update button, any idea? thanks before.

preview image

CodePudding user response：

Binding for TextBox is TwoWay by default. You need to change it to OneWay if you don't want to change the source.

<TextBox
    Grid.Column="1"
    materialDesign:HintAssist.FloatingOffset="0, -18"
    IsReadOnly="False"
    Style="{StaticResource MaterialDesignFloatingHintTextBox}"
    materialDesign:HintAssist.Hint="Document Type"
    HorizontalAlignment="Stretch"
    FontSize="14"
    Margin="0 10 0 20"
    Text="{Binding Path=CurrentDocumentType.DocumentTypeName, Mode=OneWay}" />