textbox kontrola unosa

Code:

public class TextBoxEx : TextBox
    {
        public enum TextBoxExFilterType : byte
        {
            NoFilter,
            WholeNumber,
            DecimalNumber,
            PositiveWholeNumber,
            PositiveDecimalNumber,
            NegativeWholeNumber,
            NegativeDecimalNumber,
            CustomFilter
        }

        bool _changeInPorgress = false;
        byte _decimalPlaces = 255;
        string _currentFilterPattern = string.Empty;
        string _customFilterPattern = string.Empty;        
        TextBoxExFilterType _filterType = TextBoxExFilterType.NoFilter;

        public TextBoxEx()
        {            
        }

        protected override void OnEnter(EventArgs e)
        {
            this.SelectionStart = 0;
            this.SelectionLength = this.Text.Length;
            
            base.OnEnter(e);
        }

        protected override void OnTextChanged(EventArgs e)
        {
            if (_filterType == TextBoxExFilterType.NoFilter)
                goto End;

            if (_changeInPorgress)
            {                
                _changeInPorgress = false;
                goto End;
            }

            Regex regex = new Regex(_currentFilterPattern);
            string match = regex.Match(this.Text).Value;
            if (match != this.Text)            
            {
                _changeInPorgress = true;
                this.Text = match;            
            }

            End:
                base.OnTextChanged(e);
        }

        // ovo je da se ne bi cuo onaj glubi beep kada se pritisne enter
        protected override void OnKeyDown(KeyEventArgs e)
        {
            base.OnKeyDown(e);
            if (e.KeyCode == Keys.Enter)
                e.SuppressKeyPress = true;
        }


        protected override void OnKeyPress(KeyPressEventArgs e)
        {            
            if (e.KeyChar == '\b' || _filterType == TextBoxExFilterType.NoFilter)
                goto End;

            StringBuilder sb = new StringBuilder();
            sb.Append(this.Text.Substring(0, this.SelectionStart));
            sb.Append(e.KeyChar);
            sb.Append(this.Text.Substring(this.SelectionStart + this.SelectionLength));
            string text = sb.ToString();

            Regex regex = new Regex(_currentFilterPattern);

            if (regex.Match(text).Value != text)
            {
                e.Handled = true;
                System.Media.SystemSounds.Beep.Play();
            }
            else
                _changeInPorgress = true;

            End:
                base.OnKeyPress(e);
        }        

        [Category("Filter")]
        [DefaultValue(TextBoxEx.TextBoxExFilterType.NoFilter)]
        public TextBoxExFilterType FilterType
        {
            get
            {
                return _filterType;
            }
            set
            {
                _filterType = value;
                _currentFilterPattern = GetFilterPattern(_filterType, _decimalPlaces);
                
                //refresh
                Regex regex = new Regex(_currentFilterPattern);
                this.Text = regex.Match(this.Text).Value;
            }
        }

        [Category("Filter")]
        [DefaultValue("")]        
        public string CustomFilter
        {
            get
            {
                return _customFilterPattern;
            }
            set
            {
                _customFilterPattern = value;
                if (_filterType == TextBoxExFilterType.CustomFilter)
                {
                    _currentFilterPattern = _customFilterPattern;
                    //refresh
                    Regex regex = new Regex(_currentFilterPattern);
                    this.Text = regex.Match(this.Text).Value;
                }
            }
        }

        [Category("Filter")]
        [DefaultValue((byte)255)]        
        public byte DecimaPlaces
        {
            get
            {
                return _decimalPlaces;
            }
            set
            {
                if (value < 1)
                {
                    throw new Exception("Decimal places can not be smaller then 1.");
                }
                _decimalPlaces = value;
                _currentFilterPattern = GetFilterPattern(_filterType, _decimalPlaces);
                
                //refresh
                Regex regex = new Regex(_currentFilterPattern);
                this.Text = regex.Match(this.Text).Value;
            }    
        }

        string GetFilterPattern(TextBoxExFilterType filter, byte decimalPlaces)
        {
            NumberFormatInfo nfi = System.Threading.Thread.CurrentThread.CurrentCulture.NumberFormat;

            switch (filter)
            {
                case TextBoxExFilterType.NoFilter:
                    return "";

                case TextBoxExFilterType.WholeNumber:
                    return @"[" + nfi.NegativeSign + @"]?\d*";

                case TextBoxExFilterType.DecimalNumber:
                    return @"[" + nfi.NegativeSign + @"]?\d*[" + nfi.NumberDecimalSeparator + @"]?\d{0," + decimalPlaces.ToString() + "}";

                case TextBoxExFilterType.NegativeWholeNumber:
                    return @"[" + nfi.NegativeSign + @"]\d*";

                case TextBoxExFilterType.NegativeDecimalNumber:
                    return @"[" + nfi.NegativeSign + @"]\d*[" + nfi.NumberDecimalSeparator + @"]?\d{0," + decimalPlaces.ToString() + "}";

                case TextBoxExFilterType.PositiveWholeNumber:
                    return @"\d*";

                case TextBoxExFilterType.PositiveDecimalNumber:
                    return @"\d*[" + nfi.NumberDecimalSeparator + @"]?\d{0," + decimalPlaces.ToString() + "}";

                case TextBoxExFilterType.CustomFilter:
                    return _customFilterPattern;
            }

            return "";
        }
    }