一、 SQL Server与C#类型映射

二、 类型转换代码

/// <summary>
/// SqlDbType转C#类型
/// </summary>
/// <param name="type">SQL类型</param>
/// <returns>C#类型</returns>
public static Type SqlTypeToCsharpType(SqlDbType type)
{
    switch (type)
    {
        case SqlDbType.BigInt:
            return typeof(long);
        case SqlDbType.Binary:
            return typeof(object);
        case SqlDbType.Bit:
            return typeof(bool);
        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(int);
        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(float);
        case SqlDbType.SmallDateTime:
            return typeof(DateTime);
        case SqlDbType.SmallInt:
            return typeof(short);
        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:
            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;
    }
}

/// <summary>
/// SqlServer类型字符串转SqlDbType枚举
/// </summary>
/// <param name="sqlTypeString">SqlServer类型字符串</param>
/// <returns>SqlDbType枚举</returns>
public static SqlDbType SqlTypeStringToSqlType(string sqlTypeString)
{
    if ("sql_variant".Equals(sqlTypeString, StringComparison.CurrentCultureIgnoreCase))
    {
        return SqlDbType.Variant;
    }

    SqlDbType type;
    return Enum.TryParse(sqlTypeString, true, out type)
        ? type
        : SqlDbType.Variant;
}

/// <summary>
/// SqlServer类型字符串转C#类型
/// </summary>
/// <param name="sqlTypeString">SqlServer类型字符串</param>
/// <returns>C#类型</returns>
public static Type SqlTypeStringToCsharpType(string sqlTypeString)
{
    SqlDbType sqlDbType = SqlTypeStringToSqlType(sqlTypeString);
    return SqlTypeToCsharpType(sqlDbType);
}