Vb.net 非常感谢你的帮助。这就是答案，正如普卢图尼克斯早些时候解释的那样，对于所有正在检查的不同信息来说，循环过于笨拙。因此，在这种情况下，如果语句确实是一种方法，而上面的代码更好地表达了我的意图。您可能还想看看ErrorProvider。它会放一点红色的

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非常感谢你的帮助。这就是答案，正如普卢图尼克斯早些时候解释的那样，对于所有正在检查的不同信息来说，循环过于笨拙。因此，在这种情况下，如果语句确实是一种方法，而上面的代码更好地表达了我的意图。您可能还想看看ErrorProvider。它会放一点红色的

If cboYear.SelectedIndex = -1 Then
        warningString = warningString + "Year" & vbNewLine & "Vendor" & vbNewLine & "Report"
        txtYear.ForeColor = Color.Red
        TextBox7.ForeColor = Color.Red
        txtReport.ForeColor = Color.Red
        MessageBox.Show(warningString)
    ElseIf cboVendorName.SelectedIndex = -1 Then
        warningString = warningString + "Vendor" + vbNewLine & "Report"
        txtYear.ForeColor = Color.Black
        TextBox7.ForeColor = Color.Red
        txtReport.ForeColor = Color.Red
        MessageBox.Show(warningString)
    ElseIf cboReport.SelectedIndex = -1 Then
        warningString = warningString + "Report" & vbNewLine
        txtYear.ForeColor = Color.Black
        TextBox7.ForeColor = Color.Black
        txtReport.ForeColor = Color.Red
        MessageBox.Show(warningString)
    Else
        Main.Show()
        Me.Hide()
    End If

Dim IsValid As Boolean = True
txtYear.ForeColor = Color.Black
TextBox7.ForeColor = Color.Black
txtReport.ForeColor = Color.Black

If cboYear.SelectedIndex = -1 Then
    warningString = warningString & "Year" & vbNewLine & "Vendor" & vbNewLine & "Report"
    txtYear.ForeColor = Color.Red
    TextBox7.ForeColor = Color.Red
    txtReport.ForeColor = Color.Red
    IsValid = False
End If

If cboVendorName.Enabled AndAlso cboVendorName.SelectedIndex = -1 Then
    warningString = warningString & "Vendor" & vbNewLine & "Report"
    TextBox7.ForeColor = Color.Red
    txtReport.ForeColor = Color.Red
    IsValid = False
End If

If cboReport.Enabled AndAlso cboReport.SelectedIndex = -1 Then
    warningString = warningString & "Report" & vbNewLine
    txtReport.ForeColor = Color.Red
    IsValid = False
End If

'  See note
If IsValid = False Then
    MessageBox.Show(warningString)
Else
    ' DONT use default form instances!
    Main.Show()
    Me.Hide()
End If