thisadapter.update(dat);

string str="server=localhost;uid=sa;pwd=;database=login";
conn=new SqlConnection(str);
SqlCommand cm=new SqlCommand();
cm.Connection=conn;
cm.CommandText="insert into login values(@id,@username,@usepwd)";

cm.Parameters.Add("@id",SqlDbType.Int,4);
cm.Parameters.Add("@username",SqlDbType.Char,10);
cm.Parameters.Add("@usepwd",SqlDbType.Char,10);
MessageBox.Show(dat.Rows[0][1].ToString());
cm.Parameters[0].Value=dat.Rows[0][0].ToString();
cm.Parameters[1].Value=dat.Rows[0][1].ToString();
cm.Parameters[2].Value=dat.Rows[0][2].ToString();
System.Data.SqlClient.SqlDataAdapter da=new SqlDataAdapter();
da.InsertCommand=cm;
da.Update(dat);

大家看一下我这个错在哪了。
da.Update(dat);
运行到这里就出错

[此贴子已经被作者于2006-8-27 16:22:52编辑过]

private void DataToServer_Load(object sender, System.EventArgs e)
{
BindData();
}

private void BindData()
{
DataTable dt=new DataTable();
dt.Columns.Add("编号");
dt.Columns.Add("用户名");
dt.Columns.Add("密码");
DataRow dr ;
dr = dt.NewRow(); //添加一个新列
dr["编号"] = "0001";
dr["用户名"]="bing";
dr["密码"] = "321";
dt.Rows.Add(dr);
dr =dt.NewRow(); //添加一个新列
dr["编号"] = "0002";
dr["用户名"]="bingying";
dr["密码"] = "123";
dt.Rows.Add(dr);
this.dataGrid1.DataSource = dt; //绑定数据
}

private void button1_Click(object sender, System.EventArgs e)
{
SqlConnection myconn = new SqlDbConnection("server=.;database=数据库名;uid=用户名;pwd=密码;");
myconn.Open();
SqlCommand cmd ;

DataTable dt = (DataTable)(this.dataGrid1.DataSource);
string InserStr = "";
for(int i = 0 ; i < dt.Rows.Count ; i++)
{
InserStr = "insert into users values('" + dt.Rows[i][0].ToString() + "','" + dt.Rows[i][1].ToString() + "','" + dt.Rows[i][2].ToString() + "')";
try
{
cmd = new SqlCommand(InserStr,myconn);
cmd.ExecuteNonQuery();
}
catch(Exception exp)
{
MessageBox.Show(exp.Message);
}
}
myconn.Close();
MessageBox.Show("添加成功~!");
}

[此贴子已经被作者于2006-8-27 18:21:21编辑过]

在button2_Click事件里写上:
dat=(DataTable)datagrid.datasource;
把System.Data.SqlClient.SqlDataAdapter da=new SqlDataAdapter();
da.InsertCommand=cm;
da.Update(dat);
改成:cm.ExecuteNonQuery();

你再试试看.