首先要查看ds是否存在而且是否有表及数据如果都正常则
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应该绑定DS里面的某个表如:ds.Tables(0);
下面作个简单示例，与你之上的写法不足作比较
Dim cc As ComboBox = New ComboBox
cc.Parent = Me
Dim 数据表 As New DataSet()
数据表.Tables.Add()
Dim aa As DataTable = 数据表.Tables(0)
aa.Columns.Add("lb")
aa.Rows.Add("a")
aa.Rows.Add("b")
'Dim dd As BindingSource = New BindingSource()
'dd.DataSource = 数据表.Tables(0)
'cc.DataSource = dd
cc.DataSource = 数据表.Tables(0)
cc.DisplayMember = "lb"
cc.Text = "a"
下面这段代码，是我用来计算每个月存500元进银行，连续30年，最后连本带利能有多少钱。这里面涉及复利计算。界面中右边的文本框用来输出每一次计算的结果。
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim nianxian As Integer '年限变量
Dim dingcun As Integer '定存变量
Dim fuli_big As Long '大复利
Dim fuli_small As Long '小复利
Dim i As Integer '循环变量
Dim DATAstring As String '数据字符串
nianxian = Val(年限_TextBox.Text)
dingcun = Val(定存_TextBox.Text)
DATAstring = ""
For i = 1 To nianxian
fuli_small = dingcun * (1 + 0.1875)
dingcun = fuli_small
fuli_big = fuli_big + fuli_small
DATAstring = DATAstring + "[" + Trim(Str(i)) + "]" + Str(fuli_big) + Chr(13) + Chr(10)
'DATAstring = DATAstring + "[" + Trim(Str(i)) + "]" + Str(fuli_small) + Chr(13) + Chr(10)
Next
'fuli_big = fuli_small
TextBox1.Text = DATAstring
结果_TextBox.Text = Str(fuli_big) + "元"
End Sub
需用VB实现，代码如下
'定义蛇的运动速度枚举值
Private Enum tpsSpeed
QUICKLY = 0
SLOWLY = 1
End Enum
'定义蛇的运动方向枚举值
Private Enum tpsDirection
D_UP = 38
D_DOWN = 40
D_LEFT = 37
D_RIGHT = 39
End Enum
'定义运动区域4个禁区的枚举值
Private Enum tpsForbiddenZone
FZ_TOP = 30
FZ_BOTTOM = 5330
FZ_LEFT = 30
FZ_RIGHT = 5730
End Enum
'定义蛇头及身体初始化数枚举值
Private Enum tpsSnake
SNAKEONE = 1
SNAKETWO = 2
SNAKETHREE = 3
SNAKEFOUR = 4
End Enum
'定义蛇宽度的常量
Private Const SNAKEWIDTH As Integer = 100
'该过程用于显示游戏信息
Private Sub Form_Load()
Me.Show
Me.lblTitle = "BS贪食蛇 — (版本 " App.Major "." App.Minor "." App.Revision ")"
Me.Caption = Me.lblTitle.Caption
frmSplash.Show 1
End Sub
'该过程用于使窗体恢复原始大小
Private Sub Form_Resize()
If Me.WindowState 1 Then
Me.Caption = ""
Me.Height = 6405 '窗体高度为 6405 缇
Me.Width = 8535 '窗体宽度为 8535 缇
Me.Left = (Screen.Width - Width) \ 2
Me.Top = (Screen.Height - Height) \ 2
End If
End Sub
'该过程用于重新开始开始游戏
Private Sub cmdGameStart_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
Beep
msg = MsgBox("您确认要重新开始游戏吗？", 4 + 32, "BS贪食蛇")
If msg = 6 Then Call m_subGameInitialize
End Sub
'该过程用于暂停/运行游戏
Private Sub chkPause_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Me.chkPause.Caption = "暂停游戏(P)" Then
Me.tmrSnakeMove.Enabled = False
Me.tmrGameTime.Enabled = False
Me.picMoveArea.Enabled = False
Me.lblPauseLab.Visible = True
Me.chkPause.Caption = "继续游戏(R)"
Else
Me.tmrSnakeMove.Enabled = True
Me.tmrGameTime.Enabled = True
Me.picMoveArea.Enabled = True
Me.lblPauseLab.Visible = False
Me.chkPause.Caption = "暂停游戏(P)"
End If
End Sub
'该过程用于显示游戏规则
Private Sub cmdGameRules_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
Beep
MsgBox " BS贪食蛇：一个规则最简单的趣味游戏，您将用键盘" Chr(13) _
"上的4个方向键来控制蛇的运动方向。在运动过程中蛇" Chr(13) _
"不能后退，蛇的头部也不能接触到运动区域的边线以外" Chr(13) _
"和蛇自己的身体，否则就游戏失败。在吃掉随机出现的" Chr(13) _
"果子后，蛇的身体会变长，越长难度越大。祝您好运！！", 0 + 64, "游戏规则"
End Sub
'该过程用于显示游戏开发信息
Private Sub cmdAbout_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
Beep
MsgBox "BS贪食蛇" "(V-" App.Major "." App.Minor "版本)" Chr(13) Chr(13) _
"" Chr(13) Chr(13) _
"由PigheadPrince设计制作" Chr(13) _
"CopyRight(C)2002,BestSoft.TCG", 0, "关于本游戏"
End Sub
'该过程用于退出游戏
Private Sub cmdExit_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
Beep
msg = MsgBox("您要退出本游戏吗？", 4 + 32, "BS贪食蛇")
Select Case msg
Case 6
End
Case 7
Me.chkWindowButton(2).Value = 0
Exit Sub
End Select
End Sub
'该过程用于拖动窗体_(点击图标)
Private Sub imgWindowTop_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
ReleaseCapture
SendMessage Me.hwnd, WM_SYSCOMMAND, SC_MOVE, 0
End Sub
'该共用过程用于处理窗体控制按钮组的相关操作_(锁定、最小化、退出)
Private Sub chkWindowButton_MouseUp(Index As Integer, Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button 1 Then Exit Sub
Select Case Index
Case 0 '锁定窗体
If Me.chkWindowButton(0).Value = 1 Then
Me.imgWindowTop.BorderStyle = 0
Me.imgWindowTop.Enabled = False
Else
Me.imgWindowTop.BorderStyle = 1
Me.imgWindowTop.Enabled = True
End If
Case 1 '最小化
Me.WindowState = 1
Me.chkWindowButton(1).Value = 0
Me.Caption = "BS贪食蛇 — (V-" App.Major "." App.Minor "版本)"
Case 2 '退出
Beep
msg = MsgBox("您要退出本游戏吗？", 4 + 32, "BS贪食蛇")
Select Case msg
Case 6
End
Case 7
Me.chkWindowButton(2).Value = 0
Exit Sub
End Select
End Select
End Sub
'该过程用于设置蛇运动速度的快慢
Private Sub hsbGameSpeed_Change()
Me.tmrSnakeMove.Interval = Me.hsbGameSpeed.Value
End Sub
'该过程用于通过键盘的方向键改变蛇的运动方向
Private Sub picMoveArea_KeyDown(KeyCode As Integer, Shift As Integer)
Select Case g_intDirection
Case D_UP
If KeyCode = D_DOWN Then Exit Sub
Case D_DOWN
If KeyCode = D_UP Then Exit Sub
Case D_LEFT
If KeyCode = D_RIGHT Then Exit Sub
Case D_RIGHT
If KeyCode = D_LEFT Then Exit Sub
End Select
g_intDirection = KeyCode
End Sub
'该计时循环过程用于计算游戏耗费的秒数并显示
Private Sub tmrGameTime_Timer()
g_lngGameTime = g_lngGameTime + 1
Me.lblGameTime.Caption = g_lngGameTime "秒"
End Sub
'该计时循环过程用于控制蛇的行动轨迹
Private Sub tmrSnakeMove_Timer()
Dim lngSnakeX As Long, lngSnakeY As Long, lngSnakeColor As Long
Dim lngPointX As Long, lngPointY As Long, lngPointColor As Long
Randomize
Me.picMoveArea.SetFocus
Me.picMoveArea.Cls
'确认蛇头的运动方向并获取新的位置
Select Case g_intDirection
Case D_UP '向上运动
g_udtSnake(SNAKEONE).Snake_CurX = g_udtSnake(SNAKEONE).Snake_OldX
g_udtSnake(SNAKEONE).Snake_CurY = g_udtSnake(SNAKEONE).Snake_OldY
g_udtSnake(SNAKEONE).Snake_CurY = g_udtSnake(SNAKEONE).Snake_CurY - SNAKEWIDTH
Case D_DOWN '向下运动
g_udtSnake(SNAKEONE).Snake_CurX = g_udtSnake(SNAKEONE).Snake_OldX
g_udtSnake(SNAKEONE).Snake_CurY = g_udtSnake(SNAKEONE).Snake_OldY
g_udtSnake(SNAKEONE).Snake_CurY = g_udtSnake(SNAKEONE).Snake_CurY + SNAKEWIDTH
Case D_LEFT '向左运动
g_udtSnake(SNAKEONE).Snake_CurX = g_udtSnake(SNAKEONE).Snake_OldX
g_udtSnake(SNAKEONE).Snake_CurX = g_udtSnake(SNAKEONE).Snake_CurX - SNAKEWIDTH
g_udtSnake(SNAKEONE).Snake_CurY = g_udtSnake(SNAKEONE).Snake_OldY
Case D_RIGHT '向右运动
g_udtSnake(SNAKEONE).Snake_CurX = g_udtSnake(SNAKEONE).Snake_OldX
g_udtSnake(SNAKEONE).Snake_CurX = g_udtSnake(SNAKEONE).Snake_CurX + SNAKEWIDTH
g_udtSnake(SNAKEONE).Snake_CurY = g_udtSnake(SNAKEONE).Snake_OldY
End Select
'根据新的位置绘制蛇头
lngSnakeX = g_udtSnake(SNAKEONE).Snake_CurX
lngSnakeY = g_udtSnake(SNAKEONE).Snake_CurY
lngSnakeColor = g_udtSnake(SNAKEONE).Snake_Color
Me.picMoveArea.PSet (lngSnakeX, lngSnakeY), lngSnakeColor
'移动蛇身体其他部分的位置
For i = 2 To g_intSnakeLength
g_udtSnake(i).Snake_CurX = g_udtSnake(i - 1).Snake_OldX
g_udtSnake(i).Snake_CurY = g_udtSnake(i - 1).Snake_OldY
lngSnakeX = g_udtSnake(i).Snake_CurX
lngSnakeY = g_udtSnake(i).Snake_CurY
lngSnakeColor = g_udtSnake(i).Snake_Color
Me.picMoveArea.PSet (lngSnakeX, lngSnakeY), lngSnakeColor
Next i
'更新蛇旧的坐标位置
For j = 1 To g_intSnakeLength
g_udtSnake(j).Snake_OldX = g_udtSnake(j).Snake_CurX
g_udtSnake(j).Snake_OldY = g_udtSnake(j).Snake_CurY
Next j
'判断蛇在移动中是否到了禁区而导致游戏失败
If m_funMoveForbiddenZone(g_udtSnake(SNAKEONE).Snake_CurX, g_udtSnake(SNAKEONE).Snake_CurY) Then
Beep
MsgBox "您的蛇移动到了禁区，游戏失败！", 0 + 16, "BS贪食蛇"
Me.tmrSnakeMove.Enabled = False
Me.tmrGameTime.Enabled = False
Me.picMoveArea.Visible = False
Exit Sub
End If
'判断蛇在移动中是否碰到了自己的身体而导致游戏失败
If m_funTouchSnakeBody(g_udtSnake(SNAKEONE).Snake_CurX, g_udtSnake(SNAKEONE).Snake_CurY) Then
Beep
MsgBox "您的蛇在移动中碰到了自己的身体，游戏失败！", 0 + 16, "BS贪食蛇"
Me.tmrSnakeMove.Enabled = False
Me.tmrGameTime.Enabled = False
Me.picMoveArea.Visible = False
Exit Sub
End If
'判断蛇是否吃到了果子
If m_funEatPoint(g_udtSnake(SNAKEONE).Snake_CurX, g_udtSnake(SNAKEONE).Snake_CurY) Then
'累加玩家的得分并刷新得分显示
g_intPlayerScore = g_intPlayerScore + 1
Me.lblYourScore.Caption = g_intPlayerScore "分"
Call m_subAddSnake '加长蛇的身体
Call m_subGetPoint '获取下一个果子的位置和颜色
Else
'绘制果子
lngPointX = g_udtPoint.Point_X
lngPointY = g_udtPoint.Point_Y
lngPointColor = g_udtPoint.Point_Color
Me.picMoveArea.PSet (lngPointX, lngPointY), lngPointColor
End If
End Sub
'该私有子过程用于初始化游戏
Private Sub m_subGameInitialize()
Erase g_udtSnake '清空蛇的结构数组
g_intPlayerScore = 0 '清空玩家的得分
g_lngGameTime = 0 '清空游戏耗费的秒数
g_intDirection = D_DOWN '设定蛇的初始运动方向为下
g_intSnakeLength = 4 '设定蛇的初始长度
ReDim g_udtSnake(1 To g_intSnakeLength) '重新定义蛇的长度
'定义蛇头部的数据
With g_udtSnake(SNAKEONE)
.Snake_OldX = 530
.Snake_OldY = 530
.Snake_Color = vbBlack
End With
'定义蛇身第2节的数据
With g_udtSnake(SNAKETWO)
.Snake_OldX = 530
.Snake_OldY = 430
.Snake_Color = vbGreen
End With
'定义蛇身第3节的数据
With g_udtSnake(SNAKETHREE)
.Snake_OldX = 530
.Snake_OldY = 330
.Snake_Color = vbYellow
End With
'定义蛇身第4节的数据
With g_udtSnake(SNAKEFOUR)
.Snake_OldX = 530
.Snake_OldY = 230
.Snake_Color = vbRed
End With
Me.picMoveArea.Visible = True
Me.lblYourScore.Caption = g_intPlayerScore "分"
Me.lblGameTime.Caption = g_lngGameTime "秒"
Me.tmrSnakeMove.Interval = Me.hsbGameSpeed.Value
Me.tmrSnakeMove.Enabled = True
Me.tmrGameTime.Enabled = True
Call m_subGetPoint '获取第一个果子的位置和颜色
End Sub
Dim sFileName As String
Dim Search
Private Sub dateTimeMenu_Click()
Text1.Text = Now
End Sub
Private Sub deleteMenu_Click()
Text1.Text = Left(Text1.Text, Text1.SelStart) + Mid(Text1.Text, Text1.SelStart + Text1.SelLength + 1)
End Sub
Private Sub findMenu_Click()
Search = InputBox("请输入要查找的字词：")
Dim Where1 '获取需要查找的字符串变量
Text1.SetFocus '文本框获得焦点，以显示所找到的内容Search = InputBox("请输入要查找的字词：")
Where1 = InStr(Text1.Text, Search) '在文本中查找字符串
If Where1 Then
'若找到则设置选定的起始位置并使找到的字符串高亮
Text1.SelStart = Where1 - 1
Text1.SelLength = Len(Search)
' Me.Caption = Where1 '测试用
'否则给出提示
Else: MsgBox "未找到所要查找的字符串。", vbInformation, "提示"
End If
End Sub
Private Sub findNextMenu_Click()
Dim Where2
Dim StartMe As Integer '查找的起始位置变量
Text1.SetFocus '文本框获得焦点
StartMe = Text1.SelLength + Text1.SelStart + 1 '给变量赋值
Where2 = InStr(StartMe, Text1.Text, Search) '令其从上次找到的地方找起
If Where2 Then
Text1.SelStart = Where2 - 1
Text1.SelLength = Len(Search)
Else: MsgBox "未找到所要查找的字符串.", vbInformation, "提示"
End If
End Sub
Private Sub aboutMenu_Click()
MsgBox Space(2) "文本编辑器版本号1.0" Chr(13) "由西南财经大学天府学院" Chr(13) Space(5) "肖忠 开发" Chr(13) Space(2) "copyright:天府学院"
End Sub
Private Sub allMenu_Click()
Text1.SelStart = 0
Text1.SelLength = Len(Text1.Text)
End Sub
Private Sub backcolorMenu_Click() '设置背景色代码
Form1.CommonDialog1.Action = 3
Text1.BackColor = Form1.CommonDialog1.Color
End Sub
Private Sub colorMenu_Click() '改变文字颜色代码
Form1.CommonDialog1.Action = 3
Text1.ForeColor = Form1.CommonDialog1.Color
End Sub
Private Sub cutMenu_Click()
Clipboard.SetText Text1.SelText
Text1.Text = Left(Text1.Text, Text1.SelStart) + Mid(Text1.Text, Text1.SelStart + Text1.SelLength + 1)
End Sub
Private Sub exitMenu_Click()
End
End Sub
Private Sub fontMenu_Click() '字体菜单代码
Form1.CommonDialog1.Flags = 3 Or 256
Form1.CommonDialog1.Action = 4
If Len(Form1.CommonDialog1.FontName) = 0 Then
Form1.Text1.FontName = "宋体"
Else
Form1.Text1.FontName = Form1.CommonDialog1.FontName
End If
Form1.Text1.FontSize = Form1.CommonDialog1.FontSize
If Form1.CommonDialog1.FontBold = True Then
Form1.Text1.FontBold = True
Else
Form1.Text1.FontBold = False
End If
If Form1.CommonDialog1.FontItalic = True Then
Form1.Text1.FontItalic = True
Else
Form1.Text1.FontItalic = False
End If
Text1.ForeColor = Form1.CommonDialog1.Color
End Sub
Private Sub Form_Load()
Form1.Text1.Width = Form1.Width - 130
Form1.Text1.Height = Form1.Height
End Sub
Private Sub Form_Resize()
Form1.Text1.Width = Form1.Width - 130
Form1.Text1.Height = Form1.Height
End Sub
Private Sub help1Menu_Click()
Form1.CommonDialog1.HelpCommand = cdlHelpForceFile
Form1.CommonDialog1.HelpFile = "c:\windows\system32\winhelp.hlp"
CommonDialog1.ShowHelp
End Sub
Private Sub newMenu_Click()
If Len(Trim(Text1.Text)) = 0 Then
Form1.Caption = "我的记事本" "--" "未命名"
sFileName = "未命名"
Text1.FontSize = 15
Text1.FontName = "宋体"
Text1.Text = ""
Else
Call saveAsMenu_Click
Form1.Caption = "我的记事本" "--" "未命名"
sFileName = "未命名"
Text1.FontSize = 15
Text1.FontName = "宋体"
Text1.Text = ""
End If
End Sub
Private Sub openMenu_Click() '打开文件代码
If Len(Trim(Text1.Text)) = 0 Then
Form1.Caption = "我的记事本"
Form1.CommonDialog1.Filter = "文本文件|*.txt"
Form1.CommonDialog1.Flags = 4096
Form1.CommonDialog1.Action = 1
If Len(Form1.CommonDialog1.FileName) 0 Then
sFileName = Form1.CommonDialog1.FileName
Form1.Caption = Form1.Caption "--" Form1.CommonDialog1.FileTitle
Open sFileName For Input As #1
Text1.FontSize = 15
Text1.FontName = "宋体"
Do While Not EOF(1)
Line Input #1, Text$
All$ = All$ + Text$ + Chr(13) + Chr(10)
Loop
Text1.Text = All
Close #1
End If
Else
Call saveAsMenu_Click
Form1.Caption = "我的记事本"
Form1.CommonDialog1.Filter = "文本文件|*.txt"
Form1.CommonDialog1.Flags = 4096
Form1.CommonDialog1.Action = 1
If Len(Form1.CommonDialog1.FileName) 0 Then
sFileName = Form1.CommonDialog1.FileName
Form1.Caption = Form1.Caption "--" Form1.CommonDialog1.FileTitle
Open sFileName For Input As #1
Text1.FontSize = 15
Text1.FontName = "宋体"
Do While Not EOF(1)
Line Input #1, Text$
All$ = All$ + Text$ + Chr(13) + Chr(10)
Loop
Text1.Text = All
Close #1
End If
End If
End Sub
Private Sub pasteMenu_Click() '粘贴菜单代码
Text1.Text = Left(Text1.Text, Text1.SelStart) + Clipboard.GetText() + Mid(Text1.Text, Text1.SelStart + Text1.SelLength + 1)
End Sub
Private Sub printMenu_Click()
Form1.CommonDialog1.ShowPrinter
For i = 1 To CommonDialog1.Copies
Printer.Print Text1.Text
Printer.Print Text1.Text
Next
Printer.EndDoc
End Sub
Private Sub saveAsMenu_Click() '另存为菜单代码
If Len(Trim(Text1.Text)) 0 Then
Form1.CommonDialog1.DialogTitle = "保存文件"
Form1.CommonDialog1.InitDir = "D:\"
Form1.CommonDialog1.Filter = "文本文件|*.txt"
Form1.CommonDialog1.Flags = 2
Form1.CommonDialog1.ShowSave
If Len(Form1.CommonDialog1.FileName) 0 Then
sFileName = Form1.CommonDialog1.FileName
Open sFileName For Output As #1
whole$ = Text1.Text
Print #1, whole
Close #1
End If
End If
End Sub
Private Sub saveMenu_Click()
If Len(Trim(Text1.Text)) 0 Then
Form1.CommonDialog1.DialogTitle = "保存文件"
Form1.CommonDialog1.InitDir = "D:\"
Form1.CommonDialog1.FileName = "新建文本"
Form1.CommonDialog1.Filter = "文本文件|*.txt"
Form1.CommonDialog1.Flags = 2
Form1.CommonDialog1.ShowSave
If Len(Form1.CommonDialog1.FileName) 0 Then
sFileName = Form1.CommonDialog1.FileName
Open sFileName For Output As #1
whole$ = Text1.Text
Print #1, whole
Close #1
End If
End If
End Sub
Private Sub statusMenu_Click()
End Sub
Dim url As String=" 网址"
Dim httpReq As System.Net.HttpWebRequest
Dim httpResp As System.Net.HttpWebResponse
Dim httpURL As New System.Uri(url)
httpReq = CType(WebRequest.Create(httpURL), HttpWebRequest)
httpReq.Method = "GET"
httpResp = CType(httpReq.GetResponse(), HttpWebResponse)
httpReq.KeepAlive = False ' 获取或设置一个值，该值指示是否与
Internet资源建立持久连接。
Dim reader As StreamReader = _
New StreamReader(httpResp.GetResponseStream,
System.Text.Encoding.GetEncoding(-0))
Dim respHTML As String = reader.ReadToEnd() 'respHTML就是网页源代码
Delphi代码如下：
procedure TForm1.Button1Click(Sender: TObject);
var
购物总价:Integer;
折扣:Extended;
begin
购物总价:=StrToInt(Edit1.Text);
if 购物总价250 then
begin
折扣:=0;
end
else if 购物总价500 then
begin
折扣:=0.05;
end
else if 购物总价1000 then
begin
折扣:=0.075;
end
else if 购物总价2000 then
begin
折扣:=0.1;
end
{
此段的折扣是多少？
else if 购物总价3000 then
begin
折扣:=0.05;
end
}
else if 购物总价=3000 then
begin
折扣:=0.15;
end;
ShowMessage('您享受的折扣是：'+FloatToStr(折扣)
+' 原价：'+IntToStr(购物总价)
+' 折后总价：'+FloatToStr(购物总价*(1-折扣)));
end;