如果语句带有变量字符串输入 [英] If statement with variable string input

问题描述

晚上好。我有5列的数据表，我循环。在循环内是一个if语句，分别检查每个列中的条目（行）并给出一定的结果。列被定义为H1，H2，H3，H4，H5。



我想在userform上创建一个用户输入，用户可以在其中定义逻辑if语句。例如，文本框可以是用户可以输入以下逻辑（H1> a）或（H2> a和H3< b）。>



这应该自动添加到if语句。



如有任何建议，请



我尝试了什么：



我使用了很多文本框并修改/限制了文本框中的输入，例如文本框1可以，你可以只选择带>的H1标志等，但这太有限了。

解决方案

不同的方法



看看 DataTable.Select方法（字符串）（System.Data） [< a href =https://msdn.microsoft.com/en-us/library/det4aw50%28v=vs.110%29.aspx\"target =_ blanktitle =New Window> ^ ]



获取与给定表达式匹配的所有行

很多可能性如

 H1就像F * 

看看这个CodeProject文章： Dynamic Expresso [ ^ ]



它是用C＃编写的，但你可以把它用作VB.NET的DLL。



它允许你要做这样的事情（也是C＃，我不是流利的机智h VB.NET，我希望你能读懂它）：

  string  expression =  //  表达式，例如（H1> 1）或（H2> 1和H3 <2） 
 
  var  interpreter =  new  Interpreter（）; 
 
 interpreter.SetVariable（  H1，dataTable.Rows [currentRow] [  H1]）; 
 interpreter.SetVariable（  H2，dataTable.Rows [currentRow] [  H2]）; 
 interpreter.SetVariable（  H3，dataTable.Rows [currentRow] [  H3]）; 
 
  var  detectedIdentifiers = interpreter.DetectIdentifiers（expression）; 
 
  if （detectedIdentifiers.UnknownIdentifiers.Any（））
 {
  //  显示有关无效标识符的错误消息 
  //  （例如，用户输入H4或完全不同的东西） 
} 
 
  bool  result = interpreter.Eval< bool>（表达式）; 

Good Evening. I have datatable with 5 columns through which I loop. Within the loop is an if statement checking the entry (row) in each of the columns individually and giving a certain outcome. The columns are defined as H1, H2, H3, H4, H5.

I want to create on the userform an user input, where the user can define the logic of the if statement. For instance, a text box maybe, that the user can input the following logic (H1>a) or (H2>a And H3<b).>

This should then be added to the if statement automatically.

Any suggestions, please

What I have tried:

I have using a lot of text box and fixing/limiting the inputs in the textbox, for instance textbox 1 can you can only choose H1 with > signs etc, but this is too limited.

解决方案

different approach

have a look at DataTable.Select Method (String) (System.Data)[^]

gets you all the rows matching the given Expression
lots of possibility's like

H1 like "F*"

Take a look at this CodeProject article: Dynamic Expresso[^]

It's written in C# but you can use it as a DLL from VB.NET.

It allows you to do something like this (also C#, I'm not "fluent" with VB.NET, I hope you can read it):

string expression = // expression entered by user, e.g. "(H1>1) or (H2>1 and H3<2)"

var interpreter = new Interpreter();

interpreter.SetVariable("H1", dataTable.Rows[currentRow]["H1"]);
interpreter.SetVariable("H2", dataTable.Rows[currentRow]["H2"]);
interpreter.SetVariable("H3", dataTable.Rows[currentRow]["H3"]);

var detectedIdentifiers = interpreter.DetectIdentifiers(expression);

if (detectedIdentifiers.UnknownIdentifiers.Any())
{
   // show error message about invalid identifiers
   // (e.g. user entered "H4" or something completely different)
}

bool result = interpreter.Eval<bool>(expression);

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