使用c#从数据库中获取数据
本文关键字:获取 数据 数据库 使用 | 更新日期: 2023-09-27 18:05:21
我希望从数据库中获取数据。当我给出文件名时,我想要的pageinfo
public string GetPageInfo(string filenames)
{
SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=;Integrated Security=True");
con.Open();
SqlCommand command = new SqlCommand("Select pageinfo from T_Pages where @pagename=filenames", con);
command.Parameters.AddWithValue("@pagename", "filenames");
// int result = command.ExecuteNonQuery();
using (SqlDataReader reader = command.ExecuteReader())
{
if (reader.Read())
{
Console.WriteLine(String.Format("{0}", reader["pageinfo"]));
}
}
con.Close();
}
public string GetPageInfo(string filename)
你的方法要求在块的末尾返回一个字符串。
根据您的方法流程,它必须做的最后一件事是在Console Window
如果(reader.Read ()){ Console.WriteLine(字符串。格式("{0}",读者[" pageinfo "])); }
你必须做出选择:
将
public string GetPageInfo(string filenames)
改为public void GetPageInfo(string filenames)
;或者,返回您从数据库中需要的任何列。
如果(reader.Read ()){Console.WriteLine(字符串。格式("{0}",读者("pageinfo")));}
返回读者("pageinfo");
int businessEntityID = 1;
string firstName = "Sander";
string middleName = null;
string lastName = "Rossel";
using (SqlConnection connection = new SqlConnection("Data Source=(local);Initial Catalog=AdventureWorks2014;Integrated Security=SSPI"))
using (SqlCommand cmd = new SqlCommand("UPDATE Person.Person SET FirstName = @FirstName, MiddleName = @MiddleName, LastName = @LastName WHERE BusinessEntityID = @BusinessEntityID", connection))
{
cmd.Parameters.AddWithValue("FirstName", firstName);
if (middleName == null)
{
cmd.Parameters.AddWithValue("MiddleName", DBNull.Value);
}
else
{
cmd.Parameters.AddWithValue("MiddleName", middleName);
}
cmd.Parameters.AddWithValue("LastName", lastName);
cmd.Parameters.AddWithValue("BusinessEntityID", businessEntityID);
connection.Open();
cmd.ExecuteNonQuery();
}
希望对你有帮助。