You have to use a WPF TextBox to make spell checking work. You can embed one in a Windows Forms form with the ElementHost control. It works pretty similar to a UserControl. Here's a control that you can drop straight from the toolbox. To get started, you need Project + Add Reference and select WindowsFormsIntegration, System.Design and the WPF assemblies PresentationCore, PresetationFramework and WindowsBase.
Add a new class to your project and paste the code shown below. Compile. Drop the SpellBox control from the top of the toolbox onto a form. It supports the TextChanged event and the Multiline and WordWrap properties. There's a nagging problem with the Font, there is no easy way to map a WF Font to the WPF font properties. The easiest workaround for that is to set the form's Font to "Segoe UI", the default for WPF.
using System;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Forms.Integration;
using System.Windows.Forms.Design;
[Designer(typeof(ControlDesigner))]
//[DesignerSerializer("System.Windows.Forms.Design.ControlCodeDomSerializer, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", "System.ComponentModel.Design.Serialization.CodeDomSerializer, System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
class SpellBox : ElementHost {
public SpellBox() {
box = new TextBox();
base.Child = box;
box.TextChanged += (s, e) => OnTextChanged(EventArgs.Empty);
box.SpellCheck.IsEnabled = true;
box.VerticalScrollBarVisibility = ScrollBarVisibility.Auto;
this.Size = new System.Drawing.Size(100, 20);
}
public override string Text {
get { return box.Text; }
set { box.Text = value; }
}
[DefaultValue(false)]
public bool Multiline {
get { return box.AcceptsReturn; }
set { box.AcceptsReturn = value; }
}
[DefaultValue(false)]
public bool WordWrap {
get { return box.TextWrapping != TextWrapping.NoWrap; }
set { box.TextWrapping = value ? TextWrapping.Wrap : TextWrapping.NoWrap; }
}
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public new System.Windows.UIElement Child {
get { return base.Child; }
set { /* Do nothing to solve a problem with the serializer !! */ }
}
private TextBox box;
}