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();
//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();
//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
this.DropDownList1.Items.FindByValue(dr["ClassID"].ToString().Trim()).Selected=true;
//dr为DataRow
this.DropDownList1.Items.FindByValue(dr["ClassID"].ToString().Trim()).Selected=true;
//dr为DataRow
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）
<asp:TemplateColumn HeaderText="类 别">
<ItemTemplate>
<asp:Label id=lblClass runat="server"
Text='<%# GetClassName(Convert.ToInt32(DataBinder.Eval(Container,
"DataItem.ClassID"))) %>'>
</asp:Label>
</ItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="类 别">
<ItemTemplate>
<asp:Label id=lblClass runat="server"
Text='<%# GetClassName(Convert.ToInt32(DataBinder.Eval(Container,
"DataItem.ClassID"))) %>'>
</asp:Label>
</ItemTemplate>
</asp:TemplateColumn>
（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
}
///
/// "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
}
