C# 访问数据库 Fill: SelectCommand.Connection 属性尚未初始化。

[satdown]

OleDbConnection mdb;
SqlTransaction tran = null;
            SqlCommand cmd = null;
            OleDbDataAdapter da = null;
            DataSet ds = null;
            DataRow dr = null;
            string ids = null;
            try
            {
                ds = new DataSet();
                da = new OleDbDataAdapter("select top 30 SmsIndex,SendNumber,SmsContent,SmsTime,Receiver from RecvSmsTable where NewFlag <>2 and rtrim(RecvSetIndex)<>'IP'", mdb);
                da.Fill(ds); //在这行总是提示“Fill: SelectCommand.Connection 属性尚未初始化。”
            }
            catch (System.Exception e)
            {
                ConfigSettings.Log("上行信息错误！原因：" + e.ToString());
                MessageBox.Show("上行信息错误！原因：" + e.ToString());
                return;
            }

请各位达人帮忙看下，该怎么改

[风之影子]

OleDbConnection mdb;
SqlTransaction tran = null;
            SqlCommand cmd = new SqlCommand("select top 30 SmsIndex,SendNumber,SmsContent,SmsTime,Receiver from RecvSmsTable where NewFlag <>2 and rtrim(RecvSetIndex)<>'IP'");
            OleDbDataAdapter da = null;
            DataSet ds = null;
            DataRow dr = null;
            string ids = null;
            try
            {
                ds = new DataSet();
                da = new OleDbDataAdapter(cmd, mdb);
                da.Fill(ds); //在这行总是提示“Fill: SelectCommand.Connection 属性尚未初始化。”
            }
            catch (System.Exception e)
            {
                ConfigSettings.Log("上行信息错误！原因：" + e.ToString());
                MessageBox.Show("上行信息错误！原因：" + e.ToString());
                return;
            }

改成上面的试试

[liuzxchina]

ado.net中操纵数据库有两种方式，连接的和非连接的

Console.WriteLine("***** Fun with Data Adapters *****\n");
// Hard-coded connection string.
string cnStr = "Integrated Security = SSPI;Initial Catalog=AutoLot;" +
@"Data Source=(local)\SQLEXPRESS";
// Caller creates the DataSet object.
DataSet ds = new DataSet("AutoLot");
// Inform adapter of the Select command text and connection.
SqlDataAdapter dAdapt =
new SqlDataAdapter("Select * From Inventory", cnStr);
// Fill our DataSet with a new table, named Inventory.
dAdapt.Fill(ds, "Inventory");

[dancingbit]

OleDbConnection mdb;
------------------------
只声明了连接，并没有初始化。

[我在深圳搬砖-Justin]

[Quote=引用 3 楼 dancingbit 的回复:]
OleDbConnection mdb;
------------------------
只声明了连接，并没有初始化。
[/Quote]
mdb对象需要实例化

[spursand]

OleDbConnection mdb=new OleDbConnection();
mdb.OPen();
SqlTransaction tran = null;
SqlCommand cmd = new SqlCommand("select top 30 SmsIndex,SendNumber,SmsContent,SmsTime,Receiver from RecvSmsTable where NewFlag <>2 and rtrim(RecvSetIndex)<>'IP'");
OleDbDataAdapter da = null;
DataSet ds = null;
DataRow dr = null;
string ids = null;
try
{
ds = new DataSet();
da = new OleDbDataAdapter(cmd, mdb);
da.Fill(ds); //在这行总是提示“Fill: SelectCommand.Connection 属性尚未初始化。”
}
catch (System.Exception e)
{
ConfigSettings.Log("上行信息错误！原因：" + e.ToString());
MessageBox.Show("上行信息错误！原因：" + e.ToString());
return;
}

这样试试可不可以

[dancingbit]

5L，需要指定连接字符串。