访问Array C＃中存储的信息 [英] Accessing stored information in an Array C#

问题描述

大家好，

我在我的数据库中有两个表，我在其中查询，一个名为QuestionsTable和AnswersTable。



我从AnswersTable查询questionID并将ID存储在字符串数组中。像这样：

Hi All,
I have got two table in my database in which I am querying from, one named QuestionsTable and AnswersTable.

I am querying questionIDs from the AnswersTable and storing the ID's in a string array. like this:

List<string> questionId  = new List<string>();
     

       private void button1_Click(object sender, EventArgs e)
       {
           Query = "SELECT * FROM TblAnswers WHERE UserId = '1'";
           theReader = conn.ExecuteStatement(Query);
           while (theReader.Read())
           {
        
               questionId.Add(theReader["QuestionId"].ToString());
               

           }

要访问存储在此阵列中的这些ID，我这样做：

To access these ID's stored in this array, I am doing this:

String Id = questionId[0];
           

           Query = "SELECT *  FROM QuestionsTable WHERE Id = '" + Id + "'";
           theReader = conn.ExecuteStatement(Query);
           while(theReader.Read())
           {
              question = theReader["Question"].ToString();

           }

如果上述情况我只查询一个问题尝试用户1，但我的主要问题是，让用户1尝试10个问题，我想查询并从字符串数组中访问10个问题的ID，我是否必须定义10个变量才能访问每个QuestionID？例如，我必须这样做：

In case described above I am only querying one question that "User 1" attempted but my main issue is that , lets that "User 1" attempted 10 questions and I would like to query and access the 10 questions' ID's from the string array, will I have to define 10 variables in order to access each and every QuestionID? e.g will I have to do this:

String Id = questionId[0];
String Id2 = questionId[1];
String Id3 = questionId[2];
String Id4 = questionId[3];

等等，最多10个......



我是否有更简单的方法可以在不定义10个变量的情况下访问这些ID？



我希望这是有道理的，谢谢。

and so on up to 10...

Isn't there an easier way I can access these ID's without defining 10 variables?

I hope this makes sense and thank you.

推荐答案

你可以引用数组（实际上是 List< string> ）在构造查询字符串时直接：

You can just reference the array (actually a List<string>) directly while constructing the query string:

Query = "SELECT *  FROM QuestionsTable WHERE Id = '" + questionId[nnn] + "'";

如果你想为每个人做同样的操作问题，然后把它放到一个循环中：

If you want to do the identical operation for each of the questions, then put it into a loop:

foreach (string id in questionId)
{
  Query = "SELECT *  FROM QuestionsTable WHERE Id = '" + id + "'";
  theReader = conn.ExecuteStatement(Query);
  while(theReader.Read())
  {
    question = theReader["Question"].ToString();
  }
}

你已经有这样的方式：使用 questionId ，或者，如果您想拥有一个数组并减少不必要的开销，请将其转换为数组：

You already have this way: use questionId, or, if you want to have an array and reduce unwanted overhead, convert it to array:

string[] ids = questionId.ToArray();

请参阅： http://msdn.microsoft.com/en-us/library/x303t819%28v=vs.110%29.aspx [ ^ ]。

-SA

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