public Boolean IsExist(string ID)
{
string conn = "Data Source = 192.168.214.25; Initial Catalog = BookManager; Integrated Security = SSPI";
SqlConnection myconn = new SqlConnection(conn);
SqlCommand mycomm = myconn.CreateCommand();
mycomm.CommandText = "SELECT ReaderID From Reader";
myconn.Open();
SqlDataReader readerID = mycomm.ExecuteReader();
myconn.Close();
while (readerID.Read())
{
if (readerID.GetString(0) == ID)
{
return true;
}
else
return false;
}
}请帮帮忙吧。。
{
string conn = "Data Source = 192.168.214.25; Initial Catalog = BookManager; Integrated Security = SSPI";
SqlConnection myconn = new SqlConnection(conn);
SqlCommand mycomm = myconn.CreateCommand();
mycomm.CommandText = "SELECT ReaderID From Reader";
myconn.Open();
SqlDataReader readerID = mycomm.ExecuteReader();
myconn.Close();
while (readerID.Read())
{
if (readerID.GetString(0) == ID)
{
return true;
}
else
return false;
}
}请帮帮忙吧。。
你的问题就是 while (readerID.Read())
{
if (readerID.GetString(0) == ID)
{
return true;
}
else
return false;
}
只是在有读取时才返回
while (readerID.Read())
这段代码没有返回值
myconn.Open();
SqlDataReader readerID = mycomm.ExecuteReader();
bool HasID = readerID.HasRows;
readerID.Close();
return HasID ;
{
readerID.Read();
if (readerID.GetString(0) == ID)
{
return true;
}
}
return false;