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How to: Create a Custom Formatter to Represent Decimal Values in Binary

  • 2 minutes to read

This example demonstrates a way of creating a custom formatter object to display decimal values in binary, but only if the format string is supplied as "B". See the Custom Formatting topic for information on creating custom formatters.

The result is shown in the image below.


// A custom formatter object.
public class BaseFormatter : IFormatProvider, ICustomFormatter {
    // The GetFormat method of the IFormatProvider interface.
    // This must return an object that provides formatting services for the specified type.
    public object GetFormat(Type format) {
        if (format == typeof (ICustomFormatter)) return this;
        else return null;
    // The Format method of the ICustomFormatter interface.
    // This must format the specified value according to the specified format settings.
    public string Format (string format, object arg, IFormatProvider provider) {
        if (format == null) {
            if (arg is IFormattable)
                return ((IFormattable)arg).ToString(format, provider);
                return arg.ToString(); 
        if (format == "B")
            return Convert.ToString(Convert.ToInt32(arg), 2);
            return arg.ToString();

// ...
// Assign the custom formatter to the editor.
spinEdit1.Properties.DisplayFormat.FormatType = FormatType.Custom;
spinEdit1.Properties.DisplayFormat.FormatString = "B";
spinEdit1.Properties.DisplayFormat.Format = new BaseFormatter();
spinEdit1.Properties.IsFloatValue = false;
spinEdit1.EditValue = 10;