SqlServer数据类型、C#SqlDbType对应关系及转换

 // SqlDbType转换为C#数据类型
 public static Type SqlType2CsharpType(SqlDbType sqlType)
 {
 switch (sqlType)
 {
        case SqlDbType.BigInt:
          return typeof(Int64);
        case SqlDbType.Binary:
          return typeof(Object);
        case SqlDbType.Bit:
          return typeof(Boolean);
        case SqlDbType.Char:
          return typeof(String);
        case SqlDbType.DateTime:
          return typeof(DateTime);
        case SqlDbType.Decimal:
          return typeof(Decimal);
        case SqlDbType.Float:
          return typeof(Double);
        case SqlDbType.Image:
          return typeof(Object);
        case SqlDbType.Int:
          return typeof(Int32);
        case SqlDbType.Money:
          return typeof(Decimal);
        case SqlDbType.NChar:
          return typeof(String);
        case SqlDbType.NText:
          return typeof(String);
        case SqlDbType.NVarChar:
          return typeof(String);
        case SqlDbType.Real:
          return typeof(Single);
        case SqlDbType.SmallDateTime:
          return typeof(DateTime);
        case SqlDbType.SmallInt:
          return typeof(Int16);
        case SqlDbType.SmallMoney:
          return typeof(Decimal);
        case SqlDbType.Text:
          return typeof(String);
        case SqlDbType.Timestamp:
          return typeof(Object);
        case SqlDbType.TinyInt:
          return typeof(Byte);
        case SqlDbType.Udt://自定义的数据类型
          return typeof(Object);
        case SqlDbType.UniqueIdentifier:
          return typeof(Object);
        case SqlDbType.VarBinary:
          return typeof(Object);
        case SqlDbType.VarChar:
          return typeof(String);
        case SqlDbType.Variant:
          return typeof(Object);
        case SqlDbType.Xml:
          return typeof(Object);
        default:
          return null;
 }
 }

 // sql server数据类型（如：varchar）
 // 转换为SqlDbType类型
 public static SqlDbType SqlTypeString2SqlType(string sqlTypeString)
 {
 SqlDbType dbType = SqlDbType.Variant;//默认为Object

 switch (sqlTypeString)
 {
        case "int":
          dbType = SqlDbType.Int;
          break;
        case "varchar":
          dbType = SqlDbType.VarChar;
          break;
        case "bit":
          dbType = SqlDbType.Bit;
          break;
        case "datetime":
          dbType = SqlDbType.DateTime;
          break;
        case "decimal":
          dbType = SqlDbType.Decimal;
          break;
        case "float":
          dbType = SqlDbType.Float;
          break;
        case "image":
          dbType = SqlDbType.Image;
          break;
        case "money":
          dbType = SqlDbType.Money;
          break;
        case "ntext":
          dbType = SqlDbType.NText;
          break;
        case "nvarchar":
          dbType = SqlDbType.NVarChar;
          break;
        case "smalldatetime":
          dbType = SqlDbType.SmallDateTime;
          break;
        case "smallint":
          dbType = SqlDbType.SmallInt;
          break;
        case "text":
          dbType = SqlDbType.Text;
          break;
        case "bigint":
          dbType = SqlDbType.BigInt;
          break;
        case "binary":
          dbType = SqlDbType.Binary;
          break;
        case "char":
          dbType = SqlDbType.Char;
          break;
        case "nchar":
          dbType = SqlDbType.NChar;
          break;
        case "numeric":
          dbType = SqlDbType.Decimal;
          break;
        case "real":
          dbType = SqlDbType.Real;
          break;
        case "smallmoney":
          dbType = SqlDbType.SmallMoney;
          break;
        case "sql_variant":
          dbType = SqlDbType.Variant;
          break;
        case "timestamp":
          dbType = SqlDbType.Timestamp;
          break;
        case "tinyint":
          dbType = SqlDbType.TinyInt;
          break;
        case "uniqueidentifier":
          dbType = SqlDbType.UniqueIdentifier;
          break;
        case "varbinary":
          dbType = SqlDbType.VarBinary;
          break;
        case "xml":
          dbType = SqlDbType.Xml;
          break;
 }
 return dbType;
 }

 // sql server中的数据类型，转换为C#中的类型类型
 public static Type SqlTypeString2CsharpType(string sqlTypeString)
 {
 SqlDbType dbTpe = SqlTypeString2SqlType(sqlTypeString);

 return SqlType2CsharpType(dbTpe);
 }

 // 将sql server中的数据类型，转化为C#中的类型的字符串
 public static string SqlTypeString2CsharpTypeString(string sqlTypeString)
 {
 Type type = SqlTypeString2CsharpType(sqlTypeString);

 return type.Name;
 }

原文链接：http://www.cnblogs.com/Relict/archive/2011/12/19/2293460.html