namespace Standard
{
    public class INIClass
    {
        private string strKey = "XDKJ@#*&";
        public string inipath;
        [DllImport("kernel32")]
        private static extern long WritePrivateProfileString(string section, string key, string val, string filePath);
        [DllImport("kernel32")]
        private static extern int GetPrivateProfileString(string section, string key, string def, StringBuilder retVal, int size, string filePath);
        /// <summary>
        /// 构造方法
        /// </summary>
        /// <param name="INIPath">文件路径</param>
        public INIClass(string INIPath)
        {
            inipath = INIPath;
        }
        /// <summary>
        /// 写入INI文件
        /// </summary>
        /// <param name="Section">项目名称(如 [TypeName] )</param>
        /// <param name="Key">键</param>
        /// <param name="Value">值</param>
        public void IniWriteValue(string Section, string Key, string Value)
        {
            WritePrivateProfileString(Section, Key, Value, this.inipath);
        }

        /// <summary>
        /// Md5加密写入INI文件
        /// </summary>
        /// <param name="Section">项目名称(如 [TypeName] )</param>
        /// <param name="Key">键</param>
        /// <param name="Value">值</param>
        public void IniMd5WriteValue(string Section, string Key, string Value)
        {
            string str = MD5Encrypt(Value, strKey);
            WritePrivateProfileString(Section, Key, str, this.inipath);
        }

        /// <summary>
        /// 读出INI文件
        /// </summary>
        /// <param name="Section">项目名称(如 [TypeName] )</param>
        /// <param name="Key">键</param>
        public string IniReadValue(string Section, string Key)
        {
            StringBuilder temp = new StringBuilder(500);
            int i = GetPrivateProfileString(Section, Key, "", temp, 500, this.inipath);
            return temp.ToString();
        }

        /// <summary>
        /// 读出INI文件
        /// </summary>
        /// <param name="Section">项目名称(如 [TypeName] )</param>
        /// <param name="Key">键</param>
        public string IniMd5ReadValue(string Section, string Key)
        {
            StringBuilder temp = new StringBuilder(500);
            int i = GetPrivateProfileString(Section, Key, "", temp, 500, this.inipath);
            string str = temp.ToString();

            return MD5Decrypt(str, strKey);
        }

        /// <summary>
        /// 验证文件是否存在
        /// </summary>
        /// <returns>布尔值</returns>
        public bool ExistINIFile()
        {
            return File.Exists(inipath);
        }

        ///MD5加密
        public string MD5Encrypt(string pToEncrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();

        }

        ///MD5解密
        public string MD5Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();

            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }

    }
}

假设Form2的数据要传到Form1的TextBox。

在Form2：

// Define delegate
public delegate void SendData(object sender);

// Create instance
public SendData sendData;

在Form2的按钮单击事件或其它事件代码中：

if(sendData != null)
{
　sendData(txtBoxAtForm2);
}
this.Close(); //关闭Form2

在Form1的弹出Form2的代码中：
Form2 form2 = new Form2();
form2.sendData = new Form2.SendData(MyFunction);
form2.ShowDialog();

====================

private void MyFunction(object sender)
{
 textBox1.Text = ((TextBox)sender).Text;
}

引自： C#开发和使用中的23个技巧 

１、安装水晶报表4.6(VB安装盘中自带)

2、工具箱中“选择项”将Windows\System\Crystl32.ocx添加进来。

３、将刚添加的Crystal Report Control 4.6拖到窗体上。 

///VB中的代码
　///
 //With CrystalReport1
 //    .Connect = sys_rpt.ConnectionString
 //    .WindowState = crptMaximized
 //    .ReportFileName = App.path + "\report\bustotal.rpt"
 //    .Formulas(0) = "date1='" & DTP1.Value & "'"
 //    .Formulas(1) = "date2='" & DTP2.Value & "'"
 //    .Formulas(2) = "date3='" & theApp.CompanyName & "'"
 //    .Formulas(3) = "date4='" & theApp.OperatorName & "'"
 //    .SQLQuery = pssql
 //    .Action = 1
 // End With

            string strSQL ;
            strSQL = "select * from Users";
            axCrystalReport1.Connect = "Provider=SQLOLEDB.1;Persist Security Info=True;User ID=sa;password=; Initial Catalog=DNS;Data Source=(Local)" ;
            axCrystalReport1.WindowState = Crystal.WindowStateConstants.crptMaximized;
            axCrystalReport1.ReportFileName = "User.rpt";
            axCrystalReport1.set_Formulas(0,"scomp='EKT'");　//如何传递参数，我可是找了很久，很久。
            axCrystalReport1.set_Formulas(1,"sOperate='JYSH'");

            axCrystalReport1.SQLQuery = strSQL;
            axCrystalReport1.Action = 1;