ASP.NET与数据库相关技巧_[Asp.Net教程]
					一、取得数据表 i 行 j 列的值 
//建立并打开数据库连接 
OleDbConnection conn=new OleDbConnection(); 
conn.ConnectionString=strConnectionString;//strConnectionString为数据库连接字符串 
conn.Open(); 
string sql="select * from NewsClass order by ClassId desc"; 
string x; 
DataSet ds=new DataSet(); 
OleDbDataAdapter da=new OleDbDataAdapter(sql,conn); 
da.Fill(ds,"NewsTable"); 
DataTable dt=ds.Tables["NewsTable"]; 
x=dt.Rows[i][1].ToString()//数据表i行j列的值 
conn.close(); 
二、将数据读入DropDownList 
(1)DropDownList中添加数据 
//建立并打开数据库连接 
OleDbConnection conn=new OleDbConnection(); 
conn.ConnectionString=strConnectionString;//strConnectionString为数据库连接字符串 
conn.Open(); 
string sql="select * from NewsClass order by ClassId desc"; 
//建立数据集 
DataSet ds=new DataSet(); 
OleDbDataAdapter da=new OleDbDataAdapter(sql,conn); 
da.Fill(ds,"NewsTable"); 
this.DropDownList1.DataSource=ds; 
this.DropDownList1.DataTextField = "ClassName";//Text值 
this.DropDownList1.DataValueField = "ClassID";//Value值 
this.DropDownList1.DataBind(); 
conn.Close(); 
(2)选中DropDownList的某项 
this.DropDownList1.Items.FindByValue(dr["ClassID"].ToString().Trim()).Selected=true;
//dr为DataRow 
三、分类编码检索出相应的分类名称并在DataGrid中显示 
(1).ASPX中的代码(ClassID为分类编码)
 
 
Text='<%# GetClassName(Convert.ToInt32(DataBinder.Eval(Container, 
"DataItem.ClassID"))) %>'> 
 
 
 
(2)C#代码
///  
/// "分类"列根据数字返回文字 
/// 
/// 
///  
public string GetClassName(int ClassID) 
{ 
OleDbConnection conn=new OleDbConnection(); 
conn.ConnectionString=strConnectionString; 
conn.Open(); 
string sql="select * from NewsClass where ClassID="+ClassID; 
DataSet ds=new DataSet(); 
OleDbDataAdapter da=new OleDbDataAdapter(sql,conn); 
da.Fill(ds,"ClassTable"); 
DataTable dt=ds.Tables["ClassTable"]; 
string strClassName=dt.Rows[0]["ClassName"].ToString(); 
conn.Close(); 
return strClassName;//返回 ClassID对应的ClassName 
}