类库无法正常运行 [英] Class library not functioning properly

问题描述

大家好...我试图编写一个类库，在该类库中，我处理到两个不同DB的两个不同连接.这是一些库代码...

hello guys... im trying to write a class library inwhich I handle two different connections to two different DBs. Here is some of the library code...

SqlConnection myConnection1,myConnection2;
public bool OpenAdminConnection()
{
    myConnection1 = new SqlConnection("Data Source=muze-pc\\SqlExpress; Initial Catalog=adminDB; Integrated Security=SSPI");
    try
    {
        myConnection1.Open();
        SetData(); //a function used, working properly
        return true;
    }
    catch(Exception e)
    {
        myConnection1.Close();
        return false;
    }
}
/////////////////////Second connection to 2nd DB
public void OpenTracksConnection()
{
    myConnection2 = new SqlConnection("Data Source=muze-pc\\SqlExpress; Initial Catalog=MusicDB; Integrated Security=SSPI; MultipleActiveResultSets=True");
    try
    {
        myConnection2.Open();
    }
    catch (Exception e)
    {
        myConnection2.Close();
    }
}

public int GetTotalRows()//returns number of (already distinct) records
{
    SqlCommand myComm = new SqlCommand("SELECT COUNT(*) FROM Tracks", myConnection2);
    int totalRows = 0;
    SqlDataReader dataReader;
    dataReader = myComm.ExecuteReader();
    while (dataReader.Read())
    { totalRows++; }
    dataReader.Close();
    return totalRows;
}

public void GetTrackData(int TrackId) //returns info about track using key
{
    SqlCommand myComm = new SqlCommand("SELECT * FROM Tracks WHERE TrackID = " + TrackId.ToString(), myConnection2);
    SqlDataReader dataReader;
    dataReader = myComm.ExecuteReader();
    dataReader.Read();
    td.SetTrackData(dataReader[0].ToString(),dataReader[1].ToString(),dataReader[2].ToString());
    dataReader.Close();
}

现在，connection1正确存在，但是当我在客户端中调用 GetTrackData(trackId)时，它说 dataReader 中没有数据.可能是什么原因? thnx

Now connection1 is owrking properly but when I call GetTrackData(trackId) in my client, it says that no data is present in the dataReader. What can be the reason? thnx

推荐答案

public int GetTotalRows()//returns number of (already distinct) records
{
    SqlCommand myComm = new SqlCommand("SELECT COUNT(*) FROM Tracks", myConnection2);    
    int totalRows = 0;    
    SqlDataReader dataReader;    
    dataReader = myComm.ExecuteReader();    
    while (dataReader.Read())
    { 
      totalRows++; 
    }    
    dataReader.Close();
    return totalRows;
}

返回1.

使用totalRows = Convert.ToInt32(SqlCommand.ExecuteScalar());
查询返回行数.

GetTrackData:

Returns 1.

Use totalRows = Convert.ToInt32( SqlCommand.ExecuteScalar() );
The query returns the number of rows.

GetTrackData:

if(dataReader.Read()) // Check that you actually got a result
{
  // I''d rather use the GetXXX methods
  td.SetTrackData(dataReader.GetString(0),
         dataReader.GetString(1),
         dataReader.GetString(2));
}

问候
Espen Harlinn

Regards
Espen Harlinn

GetTotalRows方法和GetTrackData方法都使用相同的SqlConnection object.我确定其中之一应该使用myConnection1代替.

Both the GetTotalRows method and the GetTrackData method use the same SqlConnection object. I''m sure one of them should use myConnection1 instead.

这几乎是一种是否插入"答案，但我认为需要提出这一问题.

当您调用

This is pretty much an "is it plugged in" type of answer, but I think it needs to be asked.

When you call

public void GetTrackData(int TrackId)

在测试过程中，您是否确定轨道"表中的记录确实存在该值?

while testing have you ensured that a record in the Tracks table actually exists with that value?

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