DataTable动态增加一列并赋值-调用应用程序配置文件-带存储过程的SqlHelper类

DataTable dt = new DataTable();

增加列：

dt.columns.add("username",Type.GetType("system.String");

dt.columns.add("age",Type.GetType("System.Int32");

赋值：

dt.Rows.add(new object[]{"黄忠",22});

在C#中如何调用应用程序配置文件(app.conifg)中的连接字符串?

如果是connectionStrings，用ConfigurationManager.ConnectionStrings["add的name"].ConnectionString;

如果是appSettings，用ConfigurationManager.AppSettings["add的key"]

带存储过程的SqlHelper类

public static class SqlHelper
{
private readonly static string strcon = ConfigurationManager.ConnectionStrings["sql"].ConnectionString;
public static int ExeucteNonQuery(string sql, CommandType type, params SqlParameter[] pms)
{
using (SqlConnection con = new SqlConnection(strcon))
{
using (SqlCommand cmd = new SqlCommand (sql,con))
{
cmd.CommandType = type;
if (pms != null)
{
cmd.Parameters.AddRange(pms);
}
con.Open();
return cmd.ExecuteNonQuery();
}
}
}
public static object ExecuteScalary(string sql, CommandType type, params SqlParameter[] pms)
{
using (SqlConnection con = new SqlConnection(strcon))
{
using (SqlCommand cmd = new SqlCommand(sql, con))
{
cmd.CommandType = type;
if (pms != null)
{
cmd.Parameters.AddRange(pms);
}
con.Open();
return cmd.ExecuteScalar();
}
}
}
public static SqlDataReader ExecuteReader(string sql, CommandType type, params SqlParameter[] pms)
{
SqlConnection con = new SqlConnection(strcon);
using (SqlCommand cmd = new SqlCommand(sql,con))
{
cmd.CommandType = type;
if (pms != null)
{
cmd.Parameters.AddRange(pms);
}
con.Open();
return cmd.ExecuteReader(CommandBehavior.CloseConnection);
}
}
public static DataTable GetTable(string sql, CommandType type, params SqlParameter[] pms)
{
using (SqlDataAdapter adapter = new SqlDataAdapter(sql,strcon))
{
adapter.SelectCommand.CommandType = type;
if (pms != null)
{
adapter.SelectCommand.Parameters.AddRange(pms);

}
DataTable table = new DataTable();
adapter.Fill(table);
return table;

}
}
}

今天面试，发现自己有太多的东西，都只是一知半解。

为美好生活，无论加艰难，都不能认输。