Textboxes are empty no need to enable a button....

Question

HI Am using wpf xaml...i have 3 textboxex and one button that button has isenabled property that is binded to other property Isfinalised....if the textbox values are empty i need to get the button disabled(isenabled false) other wise it should be in enable true mode

 

see the xaml code

<controls:ProTextBlock Text="{x:Static displayText:CommonStrings.Party_}" Grid.Row="0" Grid.Column="2" Margin="5,0,0,0" HorizontalAlignment="Left" Width="92"></controls:ProTextBlock>
<controls:ProTextBox Grid.Row="0" Grid.Column="3" HorizontalAlignment="Stretch" TabIndex="3" Margin="5,0,0,0" Height="25"
IsEnabled="{Binding InvoiceHeader.IsEnabled,UpdateSourceTrigger=PropertyChanged}"
Text="{Binding InvoiceHeader.CustomerName,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
</controls:ProTextBox>
<controls:ProTextBlock Text="Address : " Grid.Row="1" Grid.Column="2" Margin="5,0,0,0" HorizontalAlignment="Left" VerticalAlignment="Center" ></controls:ProTextBlock>
<controls:ProTextBox Grid.Row="1" Grid.Column="3" Margin="5,0,0,0" TabIndex="4"
IsEnabled="{Binding InvoiceHeader.IsEnabled,UpdateSourceTrigger=PropertyChanged}"
VerticalAlignment="Center" VerticalContentAlignment="Center"
HorizontalAlignment="Stretch" Height="25"
Text="{Binding InvoiceHeader.CustomerAddress,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
</controls:ProTextBox>
<controls:ProTextBlock Text="Phone :" Grid.Row="2" Grid.Column="2" Margin="5,0,0,0" HorizontalAlignment="Left" ></controls:ProTextBlock>
<controls:ProTextBox Grid.Row="2" Grid.Column="3" TabIndex="5" Margin="5,0,0,0"
IsEnabled="{Binding InvoiceHeader.IsEnabled,UpdateSourceTrigger=PropertyChanged}"
HorizontalAlignment="Stretch" Height="25" Text="{Binding InvoiceHeader.CustomerPhone,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}">
</controls:ProTextBox>
<controls:ProImageButton ImageType="Add"
Command="{Binding AddInvoiceDetailsCommand}" Style="{DynamicResource ImageButton}"
Background="{x:Null}"
IsEnabled="{Binding InvoiceHeader.IsEnabled,UpdateSourceTrigger=PropertyChanged}"
BorderThickness="0" />

And properties of buttons are

private bool? _isFinalized;
public bool? IsFinalized
{
get { return this._isFinalized; }
set { this.SetProperty(ref this._isFinalized, value, () => this.IsFinalized); }
}
public bool IsEnabled { get { return !Convert.ToBoolean(IsFinalized); } }
private string _customerName;
[Required]
public string CustomerName
{
get { return this._customerName; }
set { this.SetProperty(ref this._customerName, value, () => this.CustomerName); }
}
private string _customerAddress;
[Required]
public string CustomerAddress
{
get { return this._customerAddress; }
set { this.SetProperty(ref this._customerAddress, value, () => this.CustomerAddress); }
}
private string _customerPhone;
[Required]
public string CustomerPhone
{
get { return this._customerPhone; }
set { this.SetProperty(ref this._customerPhone, value, () => this.CustomerPhone); }
}

In view model i have a constructor

private InvoiceHeaderDO _invoiceHeader;
public InvoiceHeaderDO InvoiceHeader
{
get
{
return _invoiceHeader;
}
set
{
_invoiceHeader = value;
OnPropertyChanged("InvoiceHeader");
}
}
private ILookupWrapperService _lookupWrapperService;
private IFinanceWrapperService _financeWrapperService;
public ICommand SaveInvoicesCommand { get; set; }
public InvoiceDetailsViewModel()
{
_lookupWrapperService = ServiceLocator.Current.GetInstance<ILookupWrapperService>(typeof(ILookupWrapperService).Name);
_financeWrapperService = ServiceLocator.Current.GetInstance<IFinanceWrapperService>(typeof(IFinanceWrapperService).Name);
SaveInvoicesCommand = new DelegateCommand(ExecuteSaveInvoicesCommand);
}
private async void ExecuteSaveInvoicesCommand()
{
try
{
InvoiceHeader.LstInvoiceDetails = LstInvoiceDetails;
await _financeWrapperService.SaveInvoice(InvoiceHeader);
LoadData();
}
catch (Exception ex)
{
GlobalExceptionHandler.CatchException(ex);
}
}
private InvoiceHeaderDO _invoiceHeader;
public InvoiceHeaderDO InvoiceHeader
{
get
{
return _invoiceHeader;
}
set
{
_invoiceHeader = value;
OnPropertyChanged("InvoiceHeader");
}
}
private void InvoiceHeaderPropertyChanged(object sender, PropertyChangedEventArgs e)
{
var curentObject = sender as InvoiceHeaderDO;
if (InvoiceHeader == null) return;
InvoiceHeader.ValidateProperties();
switch (e.PropertyName)
{
case "CurrencyId":
var currencyObject = LstCurrency.FirstOrDefault(q => q.ID == curentObject.CurrencyId);
if (currencyObject != null)
{
curentObject.ExchangeRate = currencyObject.ExchangeRate;
}
break;
}
}