如何在循环中显示逗号分隔的详细信息？ [英] How to show details comma separated on looping?

问题描述

我想在循环中显示逗号分隔的详细信息。如果有多个，我最后会用逗号获取数据。



我尝试过：

I want to show details comma separated on looping. I am getting datas with comma at the end if there are multiple ones.

What I have tried:

foreach (DataColumn dc in Source.Columns)
                  {
                      if (ds.Tables.Count > 0)
                      {
                          if (ds.Tables[1].Rows.Count > 0)
                          {
                              if (ds.Tables[1].Rows[0]["COLUMN_NAME"].ToString() != dc.ColumnName)
                              {
                                  if(string.IsNullOrEmpty(ColumnName)==false)
                                  {
                                      ColumnName = dc.ColumnName;
                                  }
                                  else
                                  {
                                      ColumnName = ColumnName + ',';
                                  }

                              }
                          }
                      }
                      copy.ColumnMappings.Add(dc.ColumnName, dc.ColumnName);
                  }

推荐答案

不知道你想做什么，但这条线很奇怪：

Don't know what you want to do, but this line is weird:

ColumnName = ColumnName + ',';

当你不明白你的代码在做什么或为什么它做它的作用时，答案是调试器。

使用调试器查看代码正在执行的操作。只需设置断点并查看代码执行情况，调试器允许您逐行执行第1行并在执行时检查变量，这是一个令人难以置信的学习工具。



调试器 - 维基百科，免费的百科全书 [ ^ ]

掌握Visual Studio 2010中的调试 - 初学者指南 [ ^ ]



调试器在这里显示你的代码正在做什么，你的任务是与它应该做什么进行比较。

调试器中没有魔法，它没有发现错误，它只是帮助你。当代码没有达到预期的效果时，你就接近了一个错误。

When you don't understand what your code is doing or why it does what it does, the answer is debugger.
Use the debugger to see what your code is doing. Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute, it is an incredible learning tool.

Debugger - Wikipedia, the free encyclopedia[^]
Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]

The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't find bugs, it just help you to. When the code don't do what is expected, you are close to a bug.

据我所知你的问题，如果你有字符串的末尾，你会留下额外的逗号要处理的多个列。例如

As I understand your question you are left with an extra comma at the end of your string if you have more than one column to process. E.g.

"thing1, thing2, thing3,"

有几种方法可以摆脱这个逗号，这里有3个：

There are several ways to get rid of that comma, here are 3 of them:

if (ColumnName.EndsWith(","))
         ColumnName = ColumnName.TrimEnd(',');

if (ColumnName.EndsWith(","))
    ColumnName = ColumnName.Remove(ColumnName.Length - 1, 1);

(ColumnName.EndsWith(","))
   ColumnName = ColumnName.Substring(0, ColumnName.Length - 1);

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