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Walkthrough: Retrieving Dialog Box Information Collectively Using Objects

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Most Windows Forms dialog boxes have properties that expose information to the parent form. Rather than create multiple properties, you can expose a group of related data through a single dialog box property by creating a class object that stores all of the information needed by the parent form.

The following walkthrough creates a dialog box that exposes a UserInformation property containing name and e-mail address data, which is available to the parent form even after the dialog box is closed.

To create a dialog box that will expose its data through an object

  1. In Visual Studio, create a new Windows Forms project called DialogBoxObjects. For more information, see How to: Create a Windows Application Project.

  2. Add a new Form to the project and name it InformationForm. For more information, see How to: Add Windows Forms to a Project.

  3. From the Toolbox, drag a TableLayoutPanel onto the form. Use the smart tag that appears as an arrow next to the control to add a third row to the table, and use the mouse to resize the rows so that all three are equal.

  4. Add a Label to each table cell in the first column, and a TextBox to each cell in the second column. The Label controls should be named, from top to bottom, firstNameLabel, lastNameLabel, and emailLabel; the TextBox controls should be named firstNameText, lastNameText, and emailText. When you are finished, add a Button control. Name it okButton, and change the Text property to OK.

  5. Add a new Class file named UserInformation to the project.

  6. Add the public qualifier to the class definition to make this class visible outside of its namespace, and add property definitions for the FirstName, LastName and EmailAddress properties. When you are finished, the code should look like this:

Public Class UserInformation
    Private _FirstName As String = ""
    Private _LastName As String = ""
    Private _EmailAddress As String = ""

    Public Property FirstName() As String
        Get
            Return _FirstName
        End Get
        Set(ByVal value As String)
            _FirstName = value
        End Set
    End Property


    Public Property LastName() As String
        Get
            Return _LastName
        End Get
        Set(ByVal value As String)
            _LastName = value
        End Set
    End Property


    Public Property EmailAddress() As String
        Get
            Return _EmailAddress
        End Get
        Set(ByVal value As String)
            _EmailAddress = value
        End Set
    End Property
End Class

using System;
using System.Collections.Generic;
using System.Text;

namespace DialogBoxObjects
{
    public class UserInformation
    {
        private string _firstName = "";
        private string _lastName = "";
        private string _emailAddress = "";

        public string FirstName
        {
            get
            {
                return (_firstName);
            }
            set
            {
                _firstName = value;
            }
        }

        public string LastName
        {
            get
            {
                return (_lastName);
            }
            set
            {
                _lastName = value;
            }
        }

        public string EmailAddress
        {
            get
            {
                return (_emailAddress);
            }
            set
            {
                _emailAddress = value;
            }
        }
    }
}

using namespace System;
using namespace System::Collections::Generic;
using namespace System::Text;

namespace DialogBoxObjects
{
    public ref class UserInformation
    {
    public:
        UserInformation()
        {
            firstNameValue = "";
            lastNameValue = "";
            emailAddressValue = "";
        }
    private:
        String^ firstNameValue;
    private:
        String^ lastNameValue;
    private:
        String^ emailAddressValue;
    public:
        property String^ FirstName
        {
            String^ get()
            {
                return firstNameValue;
            }
            void set( String^ value )
            {
                firstNameValue = value;
            }
        }
    public:
        property String^ LastName
        {
            String^ get()
            {
                return lastNameValue;
            }
            void set( String^ value )
            {
                lastNameValue = value;
            }
        }
    public:
        property String^ EmailAddress
        {
            String^ get()
            {
                return emailAddressValue;
            }
            void set( String^ value )
            {
                emailAddressValue = value;
            }
        }
    };
}
  1. Go back to the code for InformationForm, and add a UserInformation property.
Public ReadOnly Property UserInformation() As UserInformation
    Get
        Return _UI
    End Get
End Property

public UserInformation UserInformation
{
    get
    {
        return (_ui);
    }
}

public:
    property DialogBoxObjects::UserInformation^ UserInformation
    {
        DialogBoxObjects::UserInformation^ get()
        {
            return this->userInformation;
        }
    }
  1. Handle the Validated event on each of the TextBox controls so that you can update the corresponding property on UserInformation whenever one of the values change.
Private Sub FirstNameText_Validated(ByVal sender As Object, ByVal e As EventArgs) Handles FirstNameText.Validated
    Dim FirstNameTemp As String = FirstNameText.Text.Trim()
    If FirstNameText.Text.Trim().Length > 0 Then
        _UI.FirstName = FirstNameTemp
    End If
End Sub

Private Sub LastNameText_Validated(ByVal sender As Object, ByVal e As EventArgs) Handles LastNameText.Validated
    Dim LastNameTemp As String = LastNameText.Text.Trim()
    If LastNameText.Text.Trim().Length > 0 Then
        _UI.LastName = LastNameTemp
    End If
End Sub

Private Sub EmailText_Validated(ByVal sender As Object, ByVal e As EventArgs) Handles EmailText.Validated
    Dim EmailTemp As String = EmailText.Text.Trim()
    If EmailTemp.Length > 0 Then
        _UI.EmailAddress = EmailTemp
    End If
End Sub

public InformationForm()
{
    InitializeComponent();

    firstNameText.Validated += new EventHandler(firstNameText_Validated);
    lastNameText.Validated += new EventHandler(lastNameText_Validated);
    emailText.Validated += new EventHandler(emailText_Validated);
}

void firstNameText_Validated(object sender, EventArgs e)
{
    string firstNameTemp = firstNameText.Text.Trim();
    if (firstNameText.Text.Trim().Length > 0)
    {
        _ui.FirstName = firstNameTemp;
    }
}

void lastNameText_Validated(object sender, EventArgs e)
{
    string lastNameTemp = lastNameText.Text.Trim();
    if (lastNameText.Text.Trim().Length > 0)
    {
        _ui.LastName = lastNameTemp;
    }
}

void emailText_Validated(object sender, EventArgs e)
{
    string emailTemp = emailText.Text.Trim();
    if (emailTemp.Length > 0)
    {
        _ui.EmailAddress = emailTemp;
    }
}

    private:
        void FirstNameText_Validated(Object^ sender, EventArgs^ e)
        {
            String^ firstName = firstNameText->Text->Trim();
            if (firstName->Length > 0)
            {
                userInformation->FirstName = firstName;
            }
        }

    private:
        void LastNameText_Validated(Object^ sender, EventArgs^ e)
        {
            String^ lastName = lastNameText->Text->Trim();
            if (lastName->Length > 0)
            {
                userInformation->LastName = lastName;
            }
        }

    private:
        void EmailText_Validated(Object^ sender, EventArgs^ e)
        {
            String^ email = emailText->Text->Trim();
            if (email->Length > 0)
            {
                userInformation->EmailAddress = email;
            }
        }

    private:
        void CloseFormButton_Click(Object^ sender, EventArgs^ e)
        {
            if (userInformation->FirstName->Length == 0)
            {
                MessageBox::Show("First name cannot be zero-length.");
                return;
            }
            if (userInformation->LastName->Length == 0)
            {
                MessageBox::Show("Last name cannot be zero-length.");
                return;
            }
            if (userInformation->EmailAddress->Length == 0)
            {
                MessageBox::Show("Email address cannot be zero-length.");
                return;
            }

            this->DialogResult = ::DialogResult::OK;
            this->Hide();
        }




#pragma region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
    private:
        void InitializeComponent()
        {
            this->tableLayoutPanel1 = 
                gcnew System::Windows::Forms::TableLayoutPanel();
            this->firstNameLabel = gcnew System::Windows::Forms::Label();
            this->lastNameLabel = gcnew System::Windows::Forms::Label();
            this->emailLabel = gcnew System::Windows::Forms::Label();
            this->firstNameText = gcnew System::Windows::Forms::TextBox();
            this->lastNameText = gcnew System::Windows::Forms::TextBox();
            this->emailText = gcnew System::Windows::Forms::TextBox();
            this->closeFormButton = gcnew System::Windows::Forms::Button();
            this->tableLayoutPanel1->SuspendLayout();
            this->SuspendLayout();
            //
            // tableLayoutPanel1
            //
            this->tableLayoutPanel1->ColumnCount = 2;
            this->tableLayoutPanel1->ColumnStyles->Add(
                gcnew System::Windows::Forms::ColumnStyle(
                System::Windows::Forms::SizeType::Percent, 33.98533F));
            this->tableLayoutPanel1->ColumnStyles->Add(
                gcnew System::Windows::Forms::ColumnStyle(
                System::Windows::Forms::SizeType::Percent, 66.01467F));
            this->tableLayoutPanel1->Controls->Add(this->firstNameLabel, 0, 0);
            this->tableLayoutPanel1->Controls->Add(this->lastNameLabel, 0, 1);
            this->tableLayoutPanel1->Controls->Add(this->emailLabel, 0, 2);
            this->tableLayoutPanel1->Controls->Add(this->firstNameText, 1, 0);
            this->tableLayoutPanel1->Controls->Add(this->lastNameText, 1, 1);
            this->tableLayoutPanel1->Controls->Add(this->emailText, 1, 2);
            this->tableLayoutPanel1->Location = System::Drawing::Point(33, 30);
            this->tableLayoutPanel1->Name = "tableLayoutPanel1";
            this->tableLayoutPanel1->RowCount = 3;
            this->tableLayoutPanel1->RowStyles->Add(
                gcnew System::Windows::Forms::RowStyle(
                System::Windows::Forms::SizeType::Percent, 50.0F));
            this->tableLayoutPanel1->RowStyles->Add(
                gcnew System::Windows::Forms::RowStyle(
                System::Windows::Forms::SizeType::Percent, 50.0F));
            this->tableLayoutPanel1->RowStyles->Add(
                gcnew System::Windows::Forms::RowStyle(
                System::Windows::Forms::SizeType::Absolute, 41.0F));
            this->tableLayoutPanel1->Size = System::Drawing::Size(658, 116);
            this->tableLayoutPanel1->TabIndex = 0;
            //
            // firstNameLabel
            //
            this->firstNameLabel->Anchor = 
                System::Windows::Forms::AnchorStyles::None;
            this->firstNameLabel->AutoSize = true;
            this->firstNameLabel->Location = System::Drawing::Point(82, 11);
            this->firstNameLabel->Name = "firstNameLabel";
            this->firstNameLabel->Size = System::Drawing::Size(59, 14);
            this->firstNameLabel->TabIndex = 0;
            this->firstNameLabel->Text = "First Name";
            //
            // lastNameLabel
            //
            this->lastNameLabel->Anchor = 
                System::Windows::Forms::AnchorStyles::None;
            this->lastNameLabel->AutoSize = true;
            this->lastNameLabel->Location = System::Drawing::Point(82, 48);
            this->lastNameLabel->Name = "lastNameLabel";
            this->lastNameLabel->Size = System::Drawing::Size(59, 14);
            this->lastNameLabel->TabIndex = 1;
            this->lastNameLabel->Text = "Last Name";
            //
            // emailLabel
            //
            this->emailLabel->Anchor = 
                System::Windows::Forms::AnchorStyles::None;
            this->emailLabel->AutoSize = true;
            this->emailLabel->Location = System::Drawing::Point(73, 88);
            this->emailLabel->Name = "emailLabel";
            this->emailLabel->Size = System::Drawing::Size(77, 14);
            this->emailLabel->TabIndex = 2;
            this->emailLabel->Text = "Email Address";
            //
            // firstNameText
            //
            this->firstNameText->Anchor = 
                System::Windows::Forms::AnchorStyles::None;
            this->firstNameText->Location = System::Drawing::Point(339, 8);
            this->firstNameText->Name = "firstNameText";
            this->firstNameText->Size = System::Drawing::Size(203, 20);
            this->firstNameText->TabIndex = 3;
            //
            // lastNameText
            //
            this->lastNameText->Anchor = 
                System::Windows::Forms::AnchorStyles::None;
            this->lastNameText->Location = System::Drawing::Point(339, 45);
            this->lastNameText->Name = "lastNameText";
            this->lastNameText->Size = System::Drawing::Size(202, 20);
            this->lastNameText->TabIndex = 4;
            //
            // emailText
            //
            this->emailText->Anchor = 
                System::Windows::Forms::AnchorStyles::None;
            this->emailText->Location = System::Drawing::Point(336, 85);
            this->emailText->Name = "emailText";
            this->emailText->Size = System::Drawing::Size(208, 20);
            this->emailText->TabIndex = 5;
            //
            // closeFormButton
            //
            this->closeFormButton->Location = System::Drawing::Point(550, 211);
            this->closeFormButton->Name = "closeFormButton";
            this->closeFormButton->Size = System::Drawing::Size(141, 23);
            this->closeFormButton->TabIndex = 1;
            this->closeFormButton->Text = "OK";
            this->closeFormButton->Click += gcnew System::EventHandler(this,
                &InformationForm::CloseFormButton_Click);
            //
            // InformationForm
            //
            this->AutoScaleDimensions = System::Drawing::SizeF(6.0F, 13.0F);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(744, 258);
            this->Controls->Add(this->closeFormButton);
            this->Controls->Add(this->tableLayoutPanel1);
            this->Name = "InformationForm";
            this->Text = "User Information";
            this->tableLayoutPanel1->ResumeLayout(false);
            this->tableLayoutPanel1->PerformLayout();
            this->ResumeLayout(false);

        }

#pragma endregion

    public:
        InformationForm()
        {
            userInformation = gcnew DialogBoxObjects::UserInformation;

            components = nullptr;
            InitializeComponent();

            firstNameText->Validated += gcnew EventHandler
                (this, &InformationForm::FirstNameText_Validated);
            lastNameText->Validated += gcnew EventHandler(this, 
                &InformationForm::LastNameText_Validated);
            emailText->Validated += gcnew EventHandler(this, 
                &InformationForm::EmailText_Validated);
        }
  1. Add handlers for the Validated event to each of the TextBox controls on your form, so that the new value of these controls is assigned to UserInformation whenever the user changes them.
Private Sub closeFormButton_Click(ByVal sender As Object, ByVal e As EventArgs)
    If _UI.FirstName.Length = 0 Then
        MessageBox.Show("First name cannot be zero-length.")
        Exit Sub
    End If
    If _UI.LastName.Length = 0 Then
        MessageBox.Show("Last name cannot be zero-length.")
        Exit Sub
    End If
    If _UI.EmailAddress.Length = 0 Then
        MessageBox.Show("Email address cannot be zero-length.")
        Exit Sub
    End If

    Me.DialogResult = System.Windows.Forms.DialogResult.OK
    Me.Close()
End Sub

private void closeFormButton_Click(object sender, EventArgs e)
{
    if (_ui.FirstName.Length == 0)
    {
        MessageBox.Show("First name cannot be zero-length.");
        return;
    }
    if (_ui.LastName.Length == 0)
    {
        MessageBox.Show("Last name cannot be zero-length.");
        return;
    }
    if (_ui.EmailAddress.Length == 0)
    {
        MessageBox.Show("Email address cannot be zero-length.");
        return;
    }

    this.DialogResult = DialogResult.OK;
    this.Hide();
}

private:
    void CloseFormButton_Click(Object^ sender, EventArgs^ e)
    {
        if (userInformation->FirstName->Length == 0)
        {
            MessageBox::Show("First name cannot be zero-length.");
            return;
        }
        if (userInformation->LastName->Length == 0)
        {
            MessageBox::Show("Last name cannot be zero-length.");
            return;
        }
        if (userInformation->EmailAddress->Length == 0)
        {
            MessageBox::Show("Email address cannot be zero-length.");
            return;
        }

        this->DialogResult = ::DialogResult::OK;
        this->Hide();
    }

To show the dialog box you created and retrieve the data using an object

  1. Select Form1 in Visual Studio. Add a Button to the form, and changes its Name property to showFormButton.

  2. Double-click the button to add an event handler that calls the dialog box and displays the results.

Private Sub ShowFormButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ShowFormButton.Click
    Dim InfoForm As New InformationForm()
    Dim dr As DialogResult = InfoForm.ShowDialog()
    If dr = System.Windows.Forms.DialogResult.OK Then
        Dim Txt As String = "First Name: " & InfoForm.UserInformation.FirstName + ControlChars.Cr + ControlChars.Lf
        Txt &= "Last Name: " & InfoForm.UserInformation.LastName + ControlChars.Cr + ControlChars.Lf
        Txt &= "Email Address: " & InfoForm.UserInformation.EmailAddress

        MessageBox.Show(Txt)
    End If

    InfoForm.Dispose()
End Sub

See Also

Tasks

How to: Create Dialog Boxes at Design Time
How to: Close Dialog Boxes and Retain User Input
How to: Retrieve Dialog Box Information Selectively Using Multiple Properties

Concepts

User Input to Dialog Boxes

Other Resources

Dialog Boxes in Windows Forms