再问一个问题，怎么做成combobox的自动填充

道素 2003-04-04 10:34:27

当用户再我的combobox输入内容时，比如ax
这时我希望再combobox下拉列表中列出所有ax开头的字段，其他无关不用列出就像ie的地址栏
我用DroppedDown＝true，combobox是列出所有的
我有用到了
SendMessage(cmbCartNo->Handle, CB_FINDSTRING,
cmbCartNo->ItemIndex, (long)cmbCartNo->Text.c_str());
但是都没有达到我想要的效果

还有一点补充，自动填充后，将光标定位到我输入内容的最后，后面自动填充的内容要处于选中状态，好不好实现

实在不行我就只有自己做控件了

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道素 2003-04-07

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我找到办法了：
In order to add autocomplete features to a TComboBox, you need to trap the OnKeyDown and
OnChange events. In these events you will do all of the searching, replacing, and selecting.
The Win32 ComboBox control actually _does_ have autocomplete built into it, but it is not
always implemented. To help you out with this feature, the Win32 API has several messages:

CB_FINDSTRING Finds a string based on a case-insensitive search of the first
few letters.

CB_FINDSTRINGEXACT Finds the first list box string in a combo box that matches the
string specified.

CB_SELECTSTRING Searches the list of a combo box for an item that begins with the
characters in a specified string. If a matching item is found, it
is selected and copied to the edit control.

Because of the way TComboBox is designed, we will only be using CB_FINDSTRING.
In this example, I load some data from the customers.db table from BCDEMOS to populate the
list, then trap the OnKeyDown and OnChange events.

CB_FINDSTRING takes, as its first parameter (wParam), the index of the item before the start
of the search. Since we are searching the whole list, we set it to -1.
The second parameter is the address of the string to search for.

-------------Code--------------
//cb is the ComboBox
//lastKey is a private member of TForm1

__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------

void __fastcall TForm1::FormCreate(TObject *Sender)
{
Table1->Open(); //get data from the table
Table1->First();
while (!Table1->Eof)
{
cb->Items->Add(Table1->FieldByName("Contact")->AsString);
Table1->Next();
}
}
//---------------------------------------------------------------------------
void __fastcall TForm1::cbKeyDown(TObject *Sender, WORD &Key,
TShiftState Shift)
{
lastKey = Key; //get the last key the user hit in the ComboBox
}
//---------------------------------------------------------------------------

void __fastcall TForm1::cbChange(TObject *Sender)
{
String srch = cb->Text; //text to search for
if ((lastKey == 0x08) || (lastKey == VK_DELETE)) //if they hit backspace or delete,
{ //get out of here

lastKey = 0;
return;
}
lastKey = 0;

int ix = cb->Perform(CB_FINDSTRING,-1,(LPARAM)srch.c_str()); //find the string in the list
if (ix != CB_ERR)
{
cb->ItemIndex = ix; //set the ComboBox text accordingly
cb->SelStart = srch.Length();
cb->SelLength = (cb->Text.Length()-srch.Length()); //select the appropriate text
}
}
//---------------------------------------------------------------------------

qiuafa 2003-04-07

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道素 2003-04-07

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还有就是ie的下拉部分可以调节大小怎么设置

道素 2003-04-07

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有没有更好的建议

chifengwatch 2003-04-04

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yyfzy 2003-04-04

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另外，TComboBox有自动查找功能，例如你输入ax，如果TComboBox里有以ax开头的内容时会自动查找出匹配的字符串。

yyfzy 2003-04-04

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在该TComboBox的OnExit事件里加上：
int i;
for(i=0;i<ComboBox1->Items->Count;i++)
{
//刚才输入的内容已经保存了，不在保存
if(ComboBox1->Items->Strings[i]==ComboBox1->Text)
break;
}
if(i==ComboBox1->Items->Count||ComboBox1->Items->Count==0)
{
//保存刚才输入的内容
ComboBox1->Items->Insert(0,ComboBox1->Text);
}

另外，你还可以自己完善，例如最多可用保存多少条、程序退出时把已经有的内容写到文件，以便下次程序运行时也能提示等等。