实验一代码

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim h As Integer = TextBox1.Text Dim f As Integer = TextBox2.Text Dim x As Integer = (4 * h - f) / 2 Dim y As Integer = (f - 2 * h) / 2 TextBox3.Text = x TextBox4.Text = y End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click TextBox1.Text = \"\" TextBox2.Text = \"\" TextBox4.Text = \"\" TextBox3.Text = \"\"

方法二：

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click Dim m As Integer = TextBox1.Text Dim n As Integer = TextBox2.Text Dim ji As Integer = 1 Dim tu As Integer = 1 While n <> ji * 2 + tu * 4 ji = ji + 1 tu = m - ji

If ji > m Or tu > n Then

MsgBox(\"荒唐解，请重新输入！\") TextBox1.Text = \"\" TextBox2.Text = \"\" TextBox4.Text = \"\" TextBox3.Text = \"\" Exit While End If End While

If ji < 0 Or tu < 0 Then TextBox3.Clear() TextBox4.Clear() Else

TextBox3.Text = ji TextBox4.Text = tu End If

End Sub

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click TextBox1.Text = \"\" TextBox2.Text = \"\" TextBox4.Text = \"\" TextBox3.Text = \"\" End Sub

3、求解一元二次方程

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click Dim a, b, c As Single '存放三个系数

Dim Delta, Re, Vi As Single '存放B*B-4*A*C、实部及虚部 a = Val(TextBox1.Text) '获取三个系数 b = Val(TextBox2.Text) c = Val(TextBox3.Text)

If a = 0 Then '如果a的值为0，则不是一元二次方程 TextBox4.Text = \"不是一个二次方程.\" Else

Delta = b * b - 4 * a * c '求得b*b-4*a*c并存放在变量Delta中 If Delta = 0 Then '如果Delta的值为0 Re = -b / (2 * a) '求得解 TextBox4.Text = Str(Re) '显示解 TextBox5.Text = Str(Re)

ElseIf Delta > 0 Then '如果Delta大于0，有两个解 Re = -b / (2 * a) '求得第一部分 Vi = Math.Sqrt(Delta) / (2 * a) '求得第二部分 TextBox4.Text = Str(Re + Vi) '显示第一个根 TextBox5.Text = Str(Re - Vi) '显示第二个根 Else '如果Delta小于0 Re = -b / (2 * a) '求得实部 Vi = Math.Sqrt(-Delta) / (2 * a) '求得虚部

TextBox4.Text = Str(Re) & \"+\" & Str(Vi) & \"i\" '显示第一个解 TextBox5.Text = Str(Re) & \"-\" & Str(Vi) & \"i\" '显示第二个解 End If End If End Sub

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click TextBox1.Text = \"\" TextBox2.Text = \"\" TextBox3.Text = \"\" TextBox4.Text = \"\" TextBox5.Text = \"\" End Sub

4、数组的使用。

Private Sub _4_Click(sender As Object, e As System.EventArgs) Handles Me.Click

Dim a(0 To 10) As Integer Randomize()

Dim sum As Integer, min As Integer, max As Integer sum = 0 min = 100 max = 30 For i = 0 To 9

a(i) = Int(30 + (71 * Rnd())) sum = sum + a(i)

If a(i) < min Then min = a(i) If a(i) > max Then max = a(i)

TextBox1.Text &= String.Format(\"{0}{1}\", a(i), vbTab) Next i

TextBox2.Text = max TextBox3.Text = min TextBox4.Text = sum / 10

End Sub

5、判断是否是回文数

Public Class Form1

Public Function ish(ByVal dblInput As Double) As Boolean '输入参数为Double类型,返回Boolean Dim strTemp As String Dim i As Integer Dim n As Integer

strTemp = CStr(dblInput) '转换输入为字符串类型

n = CInt(Len(strTemp) / 2) '取字符串长度的一半,如果长度为偶数,则两侧全部参加比较,

'如果为奇数,则中间位不必比较.

For i = 1 To n

If Mid(strTemp, i, 1) <> Mid(strTemp, Len(strTemp) - i + 1, 1) Then '比较左右两端. ish = False

Exit Function '发现有一次比较不相等,可以确定不是回数,退出函数,返回False. End If Next ish = True End Function

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim c As Boolean

c = ish(Val(TextBox1.Text)) If c = True Then

TextBox2.Text &= TextBox1.Text & \"*\" & vbCrLf Else

TextBox2.Text &= TextBox1.Text & vbCrLf End If

End Sub

6、单选按钮、复选框、框架、列表的使用

ComboBox控件

注意：需要修改ComboBox1的DropDownStyle属性为：Simple

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click ListBox2.Items.Add(ComboBox1.Text)

If CheckBox1.Checked Then ListBox2.Items.Add(CheckBox1.Text) If CheckBox2.Checked Then ListBox2.Items.Add(CheckBox2.Text) If CheckBox3.Checked Then ListBox2.Items.Add(CheckBox3.Text)

If RadioButton1.Checked Then ListBox2.Items.Add(RadioButton1.Text) If RadioButton2.Checked Then ListBox2.Items.Add(RadioButton2.Text) If RadioButton3.Checked Then ListBox2.Items.Add(RadioButton3.Text) If RadioButton4.Checked Then ListBox2.Items.Add(RadioButton4.Text) If RadioButton5.Checked Then ListBox2.Items.Add(RadioButton5.Text)

End Sub

7、两个窗体的使用。

Listbox控件

'随机产生10个30-100之间的整数

Private Sub 随机产生10个数据ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 随机产生10个数据ToolStripMenuItem.Click Dim a(0 To 10) As Integer

Randomize() Dim min As Integer, max As Integer min = 100 max = 30 For i = 0 To 9

a(i) = Int(30 + (71 * Rnd())) If a(i) < min Then min = a(i) If a(i) > max Then max = a(i) ListBox1.Items.Add(a(i)) Next i End Sub '删除选定的数

Private Sub 删除选定的数ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 删除选定的数ToolStripMenuItem.Click

ListBox1.Items.RemoveAt(ListBox1.SelectedIndex) End Sub '删除最小值

Private Sub 删除最小值ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 删除最小值ToolStripMenuItem.Click Dim i, m As Integer m = 0

For i = 0 To ListBox1.Items.Count - 1

If ListBox1.Items(i) < ListBox1.Items(m) Then m = i End If

Next

ListBox1.Items.RemoveAt(m) End Sub

'删除最大值

Private Sub 删除最大值ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 删除最大值ToolStripMenuItem.Click Dim i, m As Integer m = 0

For i = 0 To ListBox1.Items.Count - 1

If ListBox1.Items(i) > ListBox1.Items(m) Then m = i End If Next

ListBox1.Items.RemoveAt(m) End Sub

'统计最大值、最小值和平均值

Private Sub 统计ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 统计ToolStripMenuItem.Click 'Form4.Show()

Dim i, m, n As Integer Dim sum As Double m = 0 : n = 0

For i = 0 To ListBox1.Items.Count - 1

If ListBox1.Items(i) < ListBox1.Items(m) Then m = i End If

If ListBox1.Items(i) > ListBox1.Items(m) Then n = i End If

sum = sum + ListBox1.Items(i) Next

Dim f2 As New Form4

f2.TextBox1.Text = ListBox1.Items(m) f2.TextBox2.Text = ListBox1.Items(n)

f2.TextBox3.Text = sum / (ListBox1.Items.Count - 1) f2.Show() End Sub '添加数据

Private Sub 添加数据ToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 添加数据ToolStripMenuItem.Click Dim m As Integer

m = Val(InputBox(\"请输入一个30-100之间的整数：\", \"添加数据\", 30)) ListBox1.Items.Add(m)

End Sub

8、通用对话框RichTextBox控件的使用。 '打开文件

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click OpenFileDialog1.Filter = \"(*.txt)|*.txt|(*.rtf)|*.rtf|all file(*.*)|*.*\" OpenFileDialog1.FilterIndex = 1 OpenFileDialog1.ShowDialog() End Sub '保存文件

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click SaveFileDialog1.DefaultExt = \"rtr\" SaveFileDialog1.ShowDialog() End Sub '查找

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click Dim j% Static i% = 0

j = InStr(i + 1, RichTextBox1.Text, \".net\") If j = 0 Then

MsgBox(\"no find\") Else

RichTextBox1.Focus()

RichTextBox1.SelectionStart = j - 1 '高亮度显示查找到的字串 RichTextBox1.SelectionLength = 4 i = j End If

End Sub '结束退出

Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click End End Sub

'设置默认扩展名 '打开另存为对话框

'显示打开对话框

RichTextBox1.LoadFile(OpenFileDialog1.FileName, RichTextBoxStreamType.PlainText)

RichTextBox1.SaveFile(SaveFileDialog1.FileName, RichTextBoxStreamType.PlainText)