數據集數行

Question

我想獲得的行數的DataSet的，但這裏的代碼拋出一個異常

Dim con As New SqlConnection("server=localhost;database=MSDSS;Integrated Security=True") 
Dim i As Integer 
con.Open() 
Dim qstr As String = "Select * From SJournal" 
Dim sqladp As New SqlDataAdapter(qstr, con) 
Dim dt As New DataSet 

sqladp.Fill(dt, "SJ") 
Dim j As Integer = dt.Tables("SJ").Rows.Count 
For i = 0 To j Step 1 
    Dim rowname As String = dt.Tables("SJ").Rows(i)("JournalName") 
Next 

這是我如何計算串相似度

Dim Kq As Double = 2 
Dim Kr As Double = 1 
Dim Ks As Double = 1 
Dim ss() As Char = rowname.ToCharArray() 
Dim st() As Char = journalname.ToCharArray() 
Dim q As Integer = ss.Intersect(st).Count() 
Dim s As Integer = ss.Length - q 
Dim r As Integer = st.Length - q 
Dim total As Double = (Kq * q)/(Kq * q + Kr * r + Ks * s) 

請給我的解決方案

Answer 1

的Datatable作品等的陣列（以某種方式，當您使用它在對），和數組的索引記數從0到N-1

考慮N是數行，你應該修改這個

Dim j As Integer = dt.Tables("SJ").Rows.Count 

到

Dim j As Integer = dt.Tables("SJ").Rows.Count -1 

所以，如果有3 rows，for循環將從0變爲2

Answer 2

我期待你的for循環

For i = 0 To j Step 1 
    Dim rowname As String = dt.Tables("SJ").Rows(i)("JournalName") 
Next 

應該有j-1作爲上限，即。

For i = 0 To j-1 Step 1 
    Dim rowname As String = dt.Tables("SJ").Rows(i)("JournalName") 
Next 

Answer 3

如果您使用的是dataadapter，則無需明確打開連接。

更多參考請訪問： http://forums.asp.net/t/1663393.aspx/1