Binding::BindingComplete Event

// Represents a business object that throws exceptions when 
// invalid values are entered for some of its properties.
public ref class Part
{
private:
    String^ name;
    int number;
    double price;

public:
    Part(String^ name, int number, double price)
    {
        PartName = name;
        PartNumber = number;
        PartPrice = price;
    }

    property String^ PartName 
    {
        String^ get()
        {
            return name;
        }

        void set(String^ value)
        {
            if (value->Length <= 0)
            {
                throw gcnew Exception(
                    "Each part must have a name.");
            }
            else
            {
                name = value;
            }
        }
    }

    property double PartPrice 
    {
        double get()
        {
            return price;
        }

        void set(double value)
        {
            price = value;
        }
    }

    property int PartNumber 
    {
        int get()
        {
            return number;
        }

        void set(int value)
        {
            if (value < 100)
            {
                throw gcnew Exception(
                    "Invalid part number." \
                    "Part numbers must be " \
                    "greater than 100.");
            }
            else
            {
                number = value;
            }
        }
    }

};

ref class MainForm: public Form
{
private:
    BindingSource^ bindingSource;
    TextBox^ partNameTextBox;
    TextBox^ partNumberTextBox;
    TextBox^ partPriceTextBox;

public:
    MainForm()
    {
        bindingSource = gcnew BindingSource;
        partNameTextBox = gcnew TextBox;
        partNumberTextBox = gcnew TextBox;
        partPriceTextBox = gcnew TextBox;

        //Set up the textbox controls.
        this->partNameTextBox->Location = Point(82, 13);
        this->partNameTextBox->TabIndex = 1;
        this->partNumberTextBox->Location = Point(81, 47);
        this->partNumberTextBox->TabIndex = 2;
        this->partPriceTextBox->Location = Point(81, 83);
        this->partPriceTextBox->TabIndex = 3;

        // Add the textbox controls to the form
        this->Controls->Add(this->partNumberTextBox);
        this->Controls->Add(this->partNameTextBox);
        this->Controls->Add(this->partPriceTextBox);

        // Handle the form's Load event.
        this->Load += gcnew EventHandler(this, 
            &MainForm::OnMainFormLoad);
    }

private:

    void OnMainFormLoad(Object^ sender, EventArgs^ e)
    {   
        // Set the DataSource of bindingSource to the Part type.
        bindingSource->DataSource = Part::typeid;

        // Bind the textboxes to the properties of the Part type,
        // enabling formatting.
        partNameTextBox->DataBindings->Add(
            "Text", bindingSource, "PartName", true);
        partNumberTextBox->DataBindings->Add(
            "Text", bindingSource, "PartNumber", true);

        //Bind the textbox to the PartPrice value 
        // with currency formatting.
        partPriceTextBox->DataBindings->Add("Text", bindingSource, "PartPrice", true,
           DataSourceUpdateMode::OnPropertyChanged, nullptr, "C");

        // Handle the BindingComplete event for bindingSource and
        // the partNameBinding.
        bindingSource->BindingComplete += 
            gcnew BindingCompleteEventHandler(this, 
            &MainForm::OnBindingSourceBindingComplete);
        bindingSource->BindingComplete += 
            gcnew BindingCompleteEventHandler(this, 
            &MainForm::OnPartNameBindingBindingComplete);

        // Add a new part to bindingSource.
        bindingSource->Add(gcnew Part("Widget", 1234, 12.45));
    }

    // Handle the BindingComplete event to catch errors and 
    // exceptions in binding process.
    void OnBindingSourceBindingComplete(Object^ sender, 
        BindingCompleteEventArgs^ e)
    {
        if (e->BindingCompleteState == 
            BindingCompleteState::Exception)
        {
            MessageBox::Show(String::Format(
                CultureInfo::CurrentCulture,
                "bindingSource: {0}", e->Exception->Message));
        }

        if (e->BindingCompleteState == 
            BindingCompleteState::DataError)
        {
            MessageBox::Show(String::Format(
                CultureInfo::CurrentCulture,
                "bindingSource: {0}", e->Exception->Message));
        }
    }

    // Handle the BindingComplete event to catch errors and 
    // exceptions in binding process.
    void OnPartNameBindingBindingComplete(Object^ sender, 
        BindingCompleteEventArgs^ e)
    {
        if (e->BindingCompleteState == 
            BindingCompleteState::Exception)
        {
            MessageBox::Show(String::Format(
                CultureInfo::CurrentCulture,
                "PartNameBinding: {0}", e->Exception->Message));
        }

        if (e->BindingCompleteState == 
            BindingCompleteState::DataError)
        {
            MessageBox::Show(String::Format(
                CultureInfo::CurrentCulture,
                "PartNameBinding: {0}", e->Exception->Message));
        }
    }
};