To close db and cannot create commands from unopened database error - xamarin.android

Question

string dppath = System.IO.Path.Combine(System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal), "user.db3");
db = new SQLiteConnection(dppath);
string DELETEPASSCODE_DETAIL = "DELETE FROM Table1;";
db.Execute(DELETEPASSCODE_DETAIL);
db.Close();
Hello. When the program executes the above code and reaches the below code, I get this error: cannot create commands from unopened database
try
{
string dpPath = System.IO.Path.Combine(System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal), "user.db3");`
if (dpPath.IndexOf("user.db3") < 0)
{
CreateDB();
CreateTable();
}
else
{
if (db == null)
{
db = new SQLiteConnection(dpPath);
}
var tableExist = db.GetTableInfo("Table1");
……
The error occurs on this db.GetTableInfo("Table1");

Answer 1

I made some mistakes for the first check of the code. Now, I reproduced this issue.
The db can not be null, delete the If statement.
Change:
if (db == null)
{
db = new SQLiteConnection(_databasePath);
}
var tableExist = db.GetTableInfo("Info");
var table_Info = db.Table<Info>().ToList();
To:
db = new SQLiteConnection(_databasePath);
var tableExist = db.GetTableInfo("Info");
var table_Info = db.Table<Info>().ToList();
db.Table<Info>().ToList() could also be used to get the table information.