我遇到了问题，当我登录时发生错误，没有给出一个或多个必需参数的值。
protected void imgbtn_login_Click(object sender, ImageClickEventArgs e)
{
int UserId = 0;
string str = ("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=pathto.mdb;Persist Security Info=False;");
OleDbConnection conn = new OleDbConnection(str);
conn.Open();
string query = "select * from Users where LoginName='" + txt_logname.Text + "' and Password='" + txt_pass.Text + "';";
OleDbDataAdapter da=new OleDbDataAdapter(query,conn);
DataSet ds = new DataSet();
da.Fill(ds);
DataTable dt = new DataTable();
dt = ds.Tables[0];
try
{
UserId = Int32.Parse(dt.Rows[0]["UserId"].ToString());
//btn_LogIn.Text = "Login Succeded";
Response.Redirect("Register.aspx");
}
catch (Exception ex)
{
}
txt_logname.Text = " ";
txt_pass.Text = "";
}