Extended Text

What it is for

Use it in place of a TextBox on forms where the classic sunken 3-D edge looks out of place, or where a field should call for attention – a required field left empty, or a value that failed validation. All the editing, selection, clipboard and scrolling behaviour is the standard text box's; only the frame round it is drawn by the control.

The border

• While ExtendedState is true (the default), a one-pixel border is drawn in BorderColor, continuous or dotted (DrawBorder). With ExtendedState false the box keeps a classic sunken edge.
• With ShowBorderAlways true (the default) the border is always drawn in BorderColor. Set it to false for a hover effect: the border is drawn in BorderColorWhenControlIsNotInFocus at rest, and in BorderColor while the pointer is over the box or it has the focus.
• When the box is disabled, the control draws the greyed text itself; in the flat style it does so on a window background, with a border in BorderColorWhenControlIsDisabled.

Blinking

StartToBlink() flashes the border between a colour of your choice and BorderColor until StopBlinking is called – a quiet way to point at the field a validation message is about.

using System;
using System.Drawing;
using System.Windows.Forms;
using Binarymission.WinForms.Controls.TextControls;

public class NewCustomerForm : Form
{
    private readonly BinaryExtendedText emailBox;

    public NewCustomerForm()
    {
        Text = "New customer";
        ClientSize = new Size(340, 110);

        emailBox = new BinaryExtendedText
        {
            Location = new Point(12, 12),
            Width = 316,
            BorderColor = Color.SteelBlue,
            BorderColorWhenControlIsNotInFocus = Color.Silver,
            ShowBorderAlways = false          // grey at rest, blue under the pointer or with the focus
        };
        emailBox.TextChanged += (sender, e) => emailBox.StopBlinking();

        var saveButton = new Button { Text = "Save", Location = new Point(253, 70) };
        saveButton.Click += SaveButton_Click;

        Controls.Add(emailBox);
        Controls.Add(saveButton);
    }

    private void SaveButton_Click(object sender, EventArgs e)
    {
        if (!emailBox.Text.Contains("@"))
        {
            emailBox.StartToBlink(Color.Crimson, 400);   // flash until the user edits the field
            emailBox.Focus();
            return;
        }

        Close();
    }
}