vb combobox样式修改

'关于标准下拉框的
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Const CB_SHOWDROPDOWN = &H14F
Const CB_GETDROPPEDWIDTH = &H15F
Const CB_SETDROPPEDWIDTH = &H160

'改变下拉框的宽度,NewWidth为新宽度,可用strtmp取得最长的下拉框中的字符串,NewWidth=TextWidth(strTmp) * cbo1.FontSize / 9
SendMessage cbo1.hwnd, CB_SETDROPPEDWIDTH, NewWidth, 0

'弹出下拉框
SendMessage cbo1.hwnd, CB_SHOWDROPDOWN, True, 0


'调用关机界面，可能没什么用
Private Declare Function SHShutDownDialog Lib "shell32" Alias "#60" (ByVal YourGuess As Long) As Long
Call SHShutDownDialog(&O0)

AutoComplete ComboBox in VB.Net

2 Simple Functions to call from ComboBox events to Autocomplete. Will work with Data Bound combos.
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Introduction
This is an AutoCompleting ComboBox that works with Data Bound or Regular ComboBoxes in VB.NET. As you type the case is preserved but the remaining text is auto filled by the list items. When the Leave function is called the case is fixed and the index from the list is also selected if there is a matching item.
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Call the corresponding functions from your Combobox's KeyUp and Leave events like so:
***************************
Private Sub cboName_Leave(ByVal sender As Object, ByVal e As System.EventArgs)
Handles cboName.Leave
Dim recRowView As DataRowView
Dim recName As DB.tblNameRow

AutoCompleteCombo_Leave(cboName)

'OPTIONAL: Now you can do some extra handling if you want

'Get the Selected Record from my Data Bound Combo (Return Type is DataRowView)
recRowView = cboName.SelectedItem
If recRowView Is Nothing Then Exit Sub

'Display the Name Info (Row Type comes from my bound Dataset)
recName = recRowView.Row
lblAccountNum.Text = recName.AccountNum
lblCompanyName.Text = recName.CompanyName

End Sub

Private Sub cboName_KeyUp(ByVal sender As Object,
ByVal e As System.Windows.Forms.KeyEventArgs) Handles cboName.KeyUp

AutoCompleteCombo_KeyUp(cboName, e)

End Sub
****************************************
Here are the Generic Functions for handling the events:
******************
Public Sub AutoCompleteCombo_KeyUp(ByVal cbo As ComboBox, ByVal e As KeyEventArgs)
Dim sTypedText As String
Dim iFoundIndex As Integer
Dim oFoundItem As Object
Dim sFoundText As String
Dim sAppendText As String

'Allow select keys without Autocompleting
Select Case e.KeyCode
Case Keys.Back, Keys.Left, Keys.Right, Keys.Up, Keys.Delete, Keys.Down
Return
End Select

'Get the Typed Text and Find it in the list
sTypedText = cbo.Text
iFoundIndex = cbo.FindString(sTypedText)

'If we found the Typed Text in the list then Autocomplete
If iFoundIndex >= 0 Then

'Get the Item from the list (Return Type depends if Datasource was bound
' or List Created)
oFoundItem = cbo.Items(iFoundIndex)

'Use the ListControl.GetItemText to resolve the Name in case the Combo
' was Data bound
sFoundText = cbo.GetItemText(oFoundItem)

'Append then found text to the typed text to preserve case
sAppendText = sFoundText.Substring(sTypedText.Length)
cbo.Text = sTypedText & sAppendText

'Select the Appended Text
cbo.SelectionStart = sTypedText.Length
cbo.SelectionLength = sAppendText.Length

End If

End Sub


Public Sub AutoCompleteCombo_Leave(ByVal cbo As ComboBox)
Dim iFoundIndex As Integer

iFoundIndex = cbo.FindStringExact(cbo.Text)

cbo.SelectedIndex = iFoundIndex

End Sub

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