如何在FileHelpers中使用动态CSV分隔符
本文关键字：动态 CSV 分隔符 FileHelpers | 更新日期: 2023-09-27 18:19:35
问题：我需要阅读CSV文件。我使用FileHelpers库来实现这一点。
问题是我需要一个动态分隔符（用户定义），这意味着任何东西都可以是分隔符（逗号、分号、制表符、换行符，还有其他任何东西）。
问题是，FileHelpers在属性中定义了分隔符，这意味着在编译时。这使得它不可能动态地执行。
我可以做的是声明一个新类，它继承自一个基类，并在这个新类上设置分隔符。
[FileHelpers.DelimitedRecord(",")]
public class CommaCustomer : BaseCustomer
{
}
这样，我只需要为每个新的分隔符在基类中进行更改。问题是，我不能（也不想）为每个可能的分隔符创建一个子类。
这是我迄今为止的代码：
using System;
using System.Data;
using System.IO;
//using FileHelpers;
//using FileHelpers.RunTime;
namespace Examples
{
class MainClass
{
[STAThread]
static void Main()
{
FileHelpers.FileHelperEngine engine = new FileHelpers.FileHelperEngine(typeof(SemicolonCustomer));
// To read use:
string str = @"D:'Username'Desktop'FileHelpers_Examples_CSharp_VbNet'Data'SemicolonCustomers.txt";
//str = @"D:'Username'Desktop'FileHelpers_Examples_CSharp_VbNet'Data'CustomersDelimited.txt";
SemicolonCustomer[] custs = (SemicolonCustomer[])engine.ReadFile(str);
//Customer[] custs = (Customer[]) engine.ReadFile("yourfile.txt");
foreach (SemicolonCustomer cli in custs)
{
Console.WriteLine();
Console.WriteLine("Customer: " + cli.CustId.ToString() + " - " + cli.Name);
Console.WriteLine("Added Date: " + cli.AddedDate.ToString("d-M-yyyy"));
Console.WriteLine("Balance: " + cli.Balance.ToString());
Console.WriteLine();
Console.WriteLine("-----------------------------");
} // Next cli
Console.ReadKey();
Console.WriteLine("Writing data to a delimited file...");
Console.WriteLine();
// To write use:
//engine.WriteFile("myyourfile.txt", custs);
//If you are using .NET 2.0 or greater is
//better if you use the Generics version:
// FileHelperEngine engine = new FileHelperEngine<Customer>();
// To read use (no casts =)
// Customer[] custs = engine.ReadFile("yourfile.txt");
// To write use:
// engine.WriteFile("yourfile.txt", custs);
} // End Sub Main
} // End Class MainClass
//------------------------
// RECORD CLASS (Example, change at your will)
// TIP: Remember to use the wizard to generate this class
public class BaseCustomer
{
public int CustId;
public string Name;
public decimal Balance;
[FileHelpers.FieldConverter(FileHelpers.ConverterKind.Date, "ddMMyyyy")]
public DateTime AddedDate;
}
[FileHelpers.DelimitedRecord(";")]
public class SemicolonCustomer : BaseCustomer
{
}
[FileHelpers.DelimitedRecord(",")]
public class CommaCustomer : BaseCustomer
{
}
}
是否有可能在运行时编译一个子类
[FileHelpers.DelimitedRecord('"" + delimiter + "'")]
public class AnyDelimiterCustomer : BaseCustomer
{
}
然后在代码中引用这个运行时编译的类
我刚刚意识到有一个DelimitedFileEngine可以用另一种方式解决您的问题。
你可以直接去
var engine = new DelimitedFileEngine(typeof(BaseCustomer));
engine.Options.Delimiter = ",";
似乎BaseCustomer需要用[DelimitedRecord]属性进行修饰，否则会引发异常，但分隔符会被提供给engine.Options.Delimiter的任何内容覆盖。
以下示例使用标记为条形分隔的格式导入逗号分隔的记录。
[DelimitedRecord("|")]
public class Format1
{
public string Field1;
public string Field2;
public string Field3;
public string Field4;
}
static void Main(string[] args)
{
var engine = new DelimitedFileEngine(typeof(Format1));
// change the delimiter
engine.Options.Delimiter = ",";
// import a comma separated record
object[] importedObjects = engine.ReadString(@"a,b,c,d");
foreach (object importedObject in importedObjects)
{
if (importedObject is Format1)
{
Format1 format1 = (Format1)importedObject;
// process it (for example, check the values)
Assert.AreEqual("a", format1.Field1);
Assert.AreEqual("b", format1.Field2);
Assert.AreEqual("c", format1.Field3);
Assert.AreEqual("d", format1.Field4);
}
}
}
不，这是不可能的。
但是您可以使用FileHelper DelimitedClassBuilder来构建一个动态文件解析器，您可以在运行时设置分隔符：
DelimitedClassBuilder dcb = new DelimitedClassBuilder("Name",
"Here goes your col separator");
// You have to build your field definitions by hand now
dcb.AddField("FieldName", typeof(decimal));
...
// build the engine
DelimitedFileEngine fileEngine = new DelimitedFileEngine(dcb.CreateRecordClass());
// read the file
dynamic[] data = fileEngine.ReadFile(filePath);
您可以使用运行时类。你有两个选择。从字符串编译类
例如
// The class definition
public string mClass =
@"
[DelimitedRecord(""" + delimiter + @""")]
public class BaseCustomer
{
public int CustId;
public string Name;
public decimal Balance;
[FileHelpers.FieldConverter(FileHelpers.ConverterKind.Date, ""ddMMyyyy"")]
public DateTime AddedDate;
}
";
Type t = ClassBuilder.ClassFromString(mClass);
FileHelperEngine engine = new FileHelperEngine(t);
DataTable = engine.ReadFileAsDT("test.txt");
或者，也可以使用DelimitedClassBuilder类。
DelimitedClassBuilder cb = new DelimitedClassBuilder("BaseCustomer", delimiter);
cb.AddField("CustId", typeof(int));
cb.LastField.TrimMode = TrimMode.Both;
cb.LastField.FieldNullValue = 0;
cb.AddField("Balance", typeof(Decimal));
cb.AddField("AddedDate", typeof(DateTime));
engine = new FileHelperEngine(cb.CreateRecordClass());
DataTable dt = engine.ReadFileAsDT("test.txt");
这是可能的。但只能将序列化类型移动到单独的程序集中。
像这样：
using System;
using System.Collections.Generic;
using System.Windows.Forms;
namespace FlaechenupdateScript
{
static class Program
{
// http://www.codeproject.com/KB/cs/runtimecompiling.aspx
private static System.Reflection.Assembly BuildAssembly(string code)
{
Microsoft.CSharp.CSharpCodeProvider provider =
new Microsoft.CSharp.CSharpCodeProvider();
System.CodeDom.Compiler.ICodeCompiler compiler = provider.CreateCompiler();
System.CodeDom.Compiler.CompilerParameters compilerparams = new System.CodeDom.Compiler.CompilerParameters();
string strLocation = System.Reflection.Assembly.GetExecutingAssembly().Location;
string strBasePath = System.IO.Path.GetDirectoryName(strLocation);
string strSerializationTypes = System.IO.Path.Combine(strBasePath, "SerializationTypes.dll");
string strFileHelpersLocation = System.IO.Path.Combine(strBasePath, "FileHelpers.dll");
compilerparams.ReferencedAssemblies.Add(strSerializationTypes);
compilerparams.ReferencedAssemblies.Add(strFileHelpersLocation);
compilerparams.GenerateExecutable = false;
compilerparams.GenerateInMemory = true;
System.CodeDom.Compiler.CompilerResults results =
compiler.CompileAssemblyFromSource(compilerparams, code);
if (results.Errors.HasErrors)
{
System.Text.StringBuilder errors = new System.Text.StringBuilder("Compiler Errors :'r'n");
foreach (System.CodeDom.Compiler.CompilerError error in results.Errors)
{
errors.AppendFormat("Line {0},{1}'t: {2}'n",
error.Line, error.Column, error.ErrorText);
}
throw new Exception(errors.ToString());
}
else
{
return results.CompiledAssembly;
}
} // End Function BuildAssembly
public static Type GetClassType(Type tt, string strDelimiter)
{
string strFullTypeName = tt.FullName;
string strTypeUniqueName = System.Guid.NewGuid().ToString() + System.Guid.NewGuid().ToString() + System.Guid.NewGuid().ToString() + System.Guid.NewGuid().ToString();
strTypeUniqueName = "_" + strTypeUniqueName.Replace("-", "_");
string xx = @"
namespace CrapLord
{
[FileHelpers.IgnoreFirst]
[FileHelpers.IgnoreEmptyLines]
[FileHelpers.DelimitedRecord(""" + strDelimiter + @""")]
public class " + strTypeUniqueName + @" : " + strFullTypeName + @"
{
}
}
";
System.Reflection.Assembly a = BuildAssembly(xx);
var o = a.CreateInstance("CrapLord." + strTypeUniqueName);
Type t = o.GetType();
//System.Reflection.MethodInfo mi = t.GetMethod("EvalCode");
//var s = mi.Invoke(o, null);
return t;
}
/// <summary>
/// Der Haupteinstiegspunkt für die Anwendung.
/// </summary>
[STAThread]
static void Main()
{
//Application.EnableVisualStyles();
//Application.SetCompatibleTextRenderingDefault(false);
//Application.Run(new Form1());
Type t = GetClassType(typeof(Tools.Serialization.CSV.Customer), ",");
//FileHelpers.FileHelperEngine engine = new FileHelpers.FileHelperEngine(typeof(SemicolonCustomer));
FileHelpers.FileHelperEngine engine = new FileHelpers.FileHelperEngine(t);
string str = "path/to/datafile";
Tools.Serialization.CSV.Customer[] custs = (Tools.Serialization.CSV.Customer[])engine.ReadFile(str);
//Customer[] custs = (Customer[]) engine.ReadFile("yourfile.txt");
foreach (Tools.Serialization.CSV.Customer cli in custs)
{
Console.WriteLine();
Console.WriteLine("Customer: " + cli.CustId.ToString() + " - " + cli.Name);
Console.WriteLine("Added Date: " + cli.AddedDate.ToString("d-M-yyyy"));
Console.WriteLine("Balance: " + cli.Balance.ToString());
Console.WriteLine();
Console.WriteLine("-----------------------------");
} // Next cli
Console.WriteLine(Environment.NewLine);
Console.WriteLine(" --- Press any key to continue --- ");
Console.ReadKey();
}
}
}
SerializationTypes程序集：
using System;
using System.Collections.Generic;
using System.Text;
namespace Tools.Serialization.CSV
{
//------------------------
// RECORD CLASS (Example, change at your will)
// TIP: Remember to use the wizard to generate this class
public class Customer
{
public int CustId;
public string Name;
public decimal Balance;
[FileHelpers.FieldConverter(FileHelpers.ConverterKind.Date, "ddMMyyyy")]
public DateTime AddedDate;
}
}
也许您想使用Microsoft.VisualBasic.FileIO Namespace:中的TextFieldParser
string[] fields;
string[] delimiter = new string[] { "|" };
using (Microsoft.VisualBasic.FileIO.TextFieldParser parser =
new Microsoft.VisualBasic.FileIO.TextFieldParser(filename))
{
parser.Delimiters = delimiter;
parser.HasFieldsEnclosedInQuotes = false;
while (!parser.EndOfData)
{
fields = parser.ReadFields();
//Do what you need
}
}
添加强制转换为我解决了问题（FileHelpers V3.5.1）
var engine=新的DelimitedFileEngine（typeof（BaseCustomer））；（（FileHelpers.Options.DimitedRecordOptions）engine.Options）.Dimiter="；