C# DBHelper问题
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发布时间:2022-04-08 01:22
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热心网友
时间:2022-04-08 02:52
你从哪里得到DBHelper?
就到哪里找帮助啊.
可以推测,其GetScalar()方法执行sql语句,然后返加一个单值.
我以前用过动软.net代码生成器,其SQLDBHelper类有相似的方法,但不会完全相同,实在不行就参考一下吧。
热心网友
时间:2022-04-08 04:10
public class DBHelper
{
//属性:数据库链接对象
private static SqlConnection conn;
public static SqlConnection Conn
{
get
{
string connstr = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;
if (conn == null)
conn = new SqlConnection(connstr);
if (conn.State == ConnectionState.Closed)
conn.Open();
if (conn.State == ConnectionState.Broken)
{
conn.Close();
conn.Open();
}
return conn;
}
}
//方法:查询,DataReader
public static SqlDataReader GetReader(string SqlStr)
{
SqlCommand cmd = new SqlCommand(SqlStr, Conn);
return cmd.ExecuteReader();
}
public static SqlDataReader GetReader(string SqlStr,SqlParameter[] paras)
{
SqlCommand cmd = new SqlCommand(SqlStr, Conn);
cmd.Parameters.AddRange(paras);
return cmd.ExecuteReader();
}
//查询:DataTable
public static DataTable GetTable(string SqlStr)
{
SqlDataAdapter dap = new SqlDataAdapter(SqlStr, Conn);
DataSet ds = new DataSet();
dap.Fill(ds);
conn.Close();
return ds.Tables[0];
}
//增删改
public static bool Execute(string SqlStr)
{
SqlCommand cmd = new SqlCommand(SqlStr, Conn);
int result = cmd.ExecuteNonQuery();
conn.Close();
return result > 0;
}
//返回首行首列
public static object GetScalar(string SqlStr)
{
SqlCommand cmd = new SqlCommand(SqlStr, Conn);
object obj = cmd.ExecuteScalar();
conn.Close();
return obj;
}