界面如下：
代码如下：
Public Class Form1
Const sMax As Integer = 100
Structure StudentType
Dim strID As String
Dim strName As String
Dim sngScore As Single
End Structure
Dim udtStudent(sMax) As StudentType
Dim intCount As Integer = 0
Private Sub btnNew_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNew.Click
dgvScore.Rows.Add(txtID.Text, txtName.Text, txtScore.Text)
txtID.Focus()
udtStudent(intCount).strID = txtID.Text
udtStudent(intCount).strName = txtName.Text
udtStudent(intCount).sngScore = CSng(txtScore.Text)
intCount = intCount + 1
txtID.Text = ""
txtName.Text = ""
txtScore.Text = ""
End Sub
Private Sub btnSum_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSum.Click
Dim intPos As Integer
Dim intSum As Integer
Dim dgvAvg As Double
intSum = 0
For intPos = 0 To intCount - 1
intSum = intSum + udtStudent(intPos).sngScore
Next
If intCount > 0 Then dgvAvg = intSum / intCount
MsgBox("平均分数：" + dgvAvg.ToString)
txtID.Focus()
End Sub
Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
End
End Sub
Private Sub btnDelete_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDelete.Click
If Me.dgvScore.SelectedRows.Count > 0 AndAlso _
Not Me.dgvScore.SelectedRows(0).Index = _
Me.dgvScore.Rows.Count - 1 Then _
Me.dgvScore.Rows.RemoveAt(Me.dgvScore.SelectedRows(0).Index)
End Sub
End Class
