Ask class members assignment problem-CodePudding

 public SQLiteCommand SQLiteCommand; 
Public SQLiteConnection SQLiteConnection;

Definition of the two variables, in the first time to use normal initialization and assignment, use normal,

 
SQLiteCommand=new SQLiteCommand (); 
SQLiteCommand. Connection=SQLiteConnection; 
SQLiteCommand.Com mandText=SQLstring; 

SQLiteDataReader Dr=SQLiteCommand. ExecuteReader (); 

ListView2. BeginUpdate (); 
ListView2. The Clear (); 

While (Dr. Read ()) 
{
ColumnHeader Col=new ColumnHeader (); 
Col. Text=Dr [r]. "the Name" the ToString (); 
Col. TextAlign=HorizontalAlignment. Center; 
ListView2. Columns. The Add (Col); 
}

The second assignment when they go wrong, the teacher please help to give directions, thank you!

 
SQLstring=the string. Format (" SELECT * FROM {0} "and listBox1. SelectedItem. The ToString ()); 
SQLiteCommand.Com mandText=SQLstring;////the error 
//SQLiteCommand=new SQLiteCommand ();////if the re-initialization can be normal, but should be able to assign a value of 
SQLiteCommand. Connection=SQLiteConnection; 
Dr=SQLiteCommand. ExecuteReader ();