Sqlite 查询操作
public DataTable ExecuteDataTable(string sql){
SqliteDBHelper.conn.Open();
SQLiteDataAdapter dap = new SQLiteDataAdapter(sql, SqliteDBHelper.conn);
DataTable dt = new DataTable();
dap.Fill(dt);
SqliteDBHelper.conn.Close();
//得到执行成功返回值
return dt;
}
在 System.FormatException 中第一次偶然出现的“mscorlib.dll”类型的异常
“dap.Fill(dt)”引发了“System.FormatException”类型的异常
base {System.SystemException}: {"FormatException"} --------------------编程问答-------------------- 求解啊 取个值都不行~ --------------------编程问答-------------------- 几乎所有的程序员论坛上 你问问题几乎都没人回答你
而且有点难度更完了
你这种写法貌似不给力啊 WinForms 还是asp.net?
试试我这个
--------------------编程问答-------------------- public class BookDAL
public DataTable GetDt(string Sql){
using(SQLiteConnection con = new SQLiteConnection("连接字符串")){
using(SQLiteCommand command = new SQLiteCommand(Sql,con)){
using(SQLiteAdapter adapter = new SqlAdapter(command)){
DataTable dt = new DataTable();
adapter.Fill(dt);
return dt;
}
}
}
}
{
private const string sConn = "Data Source=D:\\Project\\MySqlite\\Sqlite\\Web\\Book;";
public static bool BookAdd(Book book)
{
try
{
using(SQLiteConnection conn=new SQLiteConnection(sConn))
{
conn.Open();
SQLiteCommand cmd = conn.CreateCommand();
cmd.CommandText = "INSERT INTO book(ID,BookName,Price) VALUES(@ID,@BookName,@Price);";
cmd.Parameters.Add(new SQLiteParameter("ID",book.BkID));
cmd.Parameters.Add(new SQLiteParameter("BookName", book.BkName));
cmd.Parameters.Add(new SQLiteParameter("Price", book.BkPrice));
int i = cmd.ExecuteNonQuery();
return i == 1;
}
}
catch
{
return false;
}
}
public static bool Update(Book book)
{
try
{
using (SQLiteConnection conn = new SQLiteConnection(sConn))
{
conn.Open();
SQLiteCommand cmd = conn.CreateCommand();
cmd.CommandText = "UPDATE Book SET BookName=@BookName,Price=@Price where ID=@ID;";
cmd.Parameters.Add(new SQLiteParameter("ID", book.BkID));
cmd.Parameters.Add(new SQLiteParameter("BookName", book.BkName));
cmd.Parameters.Add(new SQLiteParameter("Price", book.BkPrice));
int i = cmd.ExecuteNonQuery();
return i == 1;
}
}
catch (Exception)
{
//Do any logging operation here if necessary
return false;
}
}
public static bool Delete(int ID)
{
try
{
using (SQLiteConnection conn = new SQLiteConnection(sConn))
{
conn.Open();
SQLiteCommand cmd = conn.CreateCommand();
cmd.CommandText = "DELETE FROM Book WHERE ID=@ID";
cmd.Parameters.Add(new SQLiteParameter("ID", ID));
int i = cmd.ExecuteNonQuery();
return i == 1;
}
}
catch (Exception)
{
//Do any logging operation here if necessary
return false;
}
}
public static DataSet GetInfo()
{
try
{
using (SQLiteConnection conn = new SQLiteConnection(sConn))
{
DataSet ds = new DataSet();
conn.Open();
SQLiteDataAdapter da = new SQLiteDataAdapter("SELECT * FROM Book order by id desc;",conn);
da.Fill(ds);
return ds;
}
}
catch (Exception)
{
return null;
}
finally
{
}
}
public static Book GetbyID(int ID)
{
try
{
using (SQLiteConnection conn = new SQLiteConnection(sConn))
{
conn.Open();
SQLiteCommand cmd = conn.CreateCommand();
cmd.CommandText = "SELECT * FROM Book WHERE ID=@ID;";
cmd.Parameters.Add(new SQLiteParameter("ID", ID));
SQLiteDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
Book book = new Book();
book.BkID = dr.GetInt32(0);
book.BkName = dr.GetString(1);
book.BkPrice = dr.GetDecimal(2);
return book;
}
else
return null;
}
}
catch (Exception)
{
return null;
}
}
}
补充:.NET技术 , C#