Validations for Date, E-Mail, All Caps, Numeric Values

class Validation {
    Boolean ValiedOBject = false;
    string str = "";

    //Property Section

    private string E_mail {
        get {
            return str;
        }
        set {
            str = value;
            Valied_Emails();
        }
    }
    // End Property Section

    private void Valied_Emails() {
        specharacter1();
        AllCaps();
    }
    private void specharacter1() {
        string spl;
        int i;
        spl = "!@%^&*()+{[}]|\\;,?<>\'~` ";
        for (i = 0;
        (i <= (spl.Length - 1)); i++) {
            if ((str.IndexOf(spl[i])) == 1) {
                ValiedOBject = false;
                return;
            }
        }
    }

    private void AllCaps() {
        int i;
        int l;
        char[] str1;
        str1 = str.Trim().ToCharArray();
        l = str.Length;
        for (i = 0;
        (i <= (l - 1)); i++) {
            if (((str1[i] >= Convert.ToChar("A")) && (str1[i] <= Convert.ToChar("Z")))) {
                ValiedOBject = false;
                return;
            }
        }
    }

    public string RemoveLastComa(string str) {
        string Newstr = "";
        int lstIndex = str.LastIndexOf(",");

        Newstr = str.Remove(lstIndex, 1);
        return Newstr;
    }

    public void FunSetFormat(System.Windows.Forms.TextBox txt) {
        txt.BackColor = System.Drawing.Color.LavenderBlush;
        txt.ForeColor = System.Drawing.Color.Navy;
        if (!txt.Font.Bold == true) {
            txt.Font = new System.Drawing.Font(txt.Font, System.Drawing.FontStyle.Bold);
        }
    }
    public void FunUnsetFormat(System.Windows.Forms.TextBox txt) {
        txt.BackColor = System.Drawing.Color.White;
        txt.ForeColor = System.Drawing.Color.Black;
        if (txt.Font.Bold == true) {
            txt.Font = new System.Drawing.Font(txt.Font, System.Drawing.FontStyle.Regular);
        }
    }

    public void SetFrmSize(System.Windows.Forms.Form frm) {
        frm.Width = 742;
        frm.Height = 697;
        frm.Location = new System.Drawing.Point(0, 0);
    }

    public Boolean IsNumeric(object Expression) {

        bool isNum;
        double retNum;
        isNum = Double.TryParse(Convert.ToString(Expression), System.Globalization.NumberStyles.Any, System.Globalization.NumberFormatInfo.InvariantInfo, out retNum);
        return isNum;
    }

    public void DateValid(TextBox mtbDate) {
        //12/12/2009
        string str = null;
        string[] arr = null;
        int pos = 0;
        char splt = '/';
        //mtbDate.Text = "12/12-2009"
        if (mtbDate.TextLength != 10) {
            MessageBox.Show("Date is not Valid Please use DD/MM/YYYY format.");
            mtbDate.Clear();
            mtbDate.Focus();
            return;
        } else {

            pos = mtbDate.Text.Trim().IndexOf('/');
            if (pos != 0 & pos == 2) {
                pos = mtbDate.Text.Trim().IndexOf('/', pos + 1);
            } else {
                MessageBox.Show("Date is not Valid Please use DD/MM/YYYY format.");
                mtbDate.Clear();
                mtbDate.Focus();
                return;
            }
            if (pos == 0) {
                MessageBox.Show("Date is not Valid Please use DD/MM/YYYY format.");
                mtbDate.Clear();
                mtbDate.Focus();
                return;
            }
        }

        str = mtbDate.Text;
        arr = str.Split(splt);
        if (!string.IsNullOrEmpty(arr[0]) & !string.IsNullOrEmpty(arr[1]) & !string.IsNullOrEmpty(arr[2]) & IsNumeric(arr[0]) == true & IsNumeric(arr[1]) == true & IsNumeric(arr[2]) == true) {
            if (Convert.ToInt16(arr[0]) <= 0 | Convert.ToInt16(arr[0]) > 31) {
                MessageBox.Show("Date is not Valid Please use DD/MM/YYYY format.");
                mtbDate.Clear();
                mtbDate.Focus();
                return;
            } else if (Convert.ToInt16(arr[1]) <= 0 | Convert.ToInt16(arr[1]) > 12) {
                MessageBox.Show("Date is not Valid Please use DD/MM/YYYY format.");
                mtbDate.Clear();
                mtbDate.Focus();
            } else if (arr[2].Length != 4) {
                MessageBox.Show("Date is not Valid Please use DD/MM/YYYY format.");
                mtbDate.Clear();
                mtbDate.Focus();
            }
        } else {
            MessageBox.Show("Date is not Valid Please use DD/MM/YYYY format.");
            mtbDate.Clear();
            mtbDate.Focus();
            return;
        }
    }