为什么 i = mycmd.ExecuteNonQuery() 返回的i都是-1呢

[happymingnan]

Dim myconn As New SqlConnection
myconn.ConnectionString = "Data Source=zjnuv;Initial Catalog=zjnuexam;User Id=sa;Password=sa;"
myconn.Open()

Dim sql As String
Dim ST_ID, PassKey As String
ST_ID = TB_ST_ID.Text.Trim()
PassKey = TB_PassKey.Text.Trim()

sql = "select Passkey from student_info where ST_ID= '" & ST_ID & "' and PassKey='" & PassKey & "'"

Dim mycmd As New SqlCommand
mycmd.Connection = myconn
mycmd.CommandText = sql

Dim i As Int32
i = mycmd.ExecuteNonQuery()
If i = 0 Then
LblMsg.Text = i.ToString
Else
LblMsg.Text = i.ToString
End If

[happymingnan]

返回的 i = mycmd.ExecuteNonQuery() i都是-1
怎么会这样的

[tianweima]

当insert或update时ExecuteNonQuery()返回受影响的行数
当为select时反回-1

[ga3ga3]

myconn.state=open ???

please do

myconn.open

==Ga3Ga3==
[e-mail]

[CMIC]

ExecuteNonQuery 对于 UPDATE、INSERT 和 DELETE 语句，返回值为该命令所影响的行数。对于其他所有类型的语句，返回值为 -1。

[比尔咔咔]

楼上的`正解啊