Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
Dim sqldr As SqlClient.SqlDataReader
Dim selectcmd As SqlClient.SqlCommand
selectcmd.CommandText = "select pcode from party where " & TextBox1.Text & "=pno"
selectcmd.CommandType = CommandType.Text
SqlConnection1.Open() '打開連接
sqldr = selectcmd.ExecuteReader(CommandBehavior.SingleResult)
If (sqldr.Read) Then
If (TextBox2.Text = selectcmd.CommandText) Then
DataGridView1.Show()
Button1.Show()
Button2.Show()
Else
MsgBox("密碼錯誤", , "提示")
End If
End If
SqlConnection1.Close()
每次都提示變數”selectcmd “在賦值前被使用 是怎么回事？
uj5u.com熱心網友回復：
定義變數的時候要加new關鍵字或在使用前使用new賦值.....轉載請註明出處，本文鏈接：https://www.uj5u.com/gongcheng/103770.html
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