如何计算文本框中的行数？

Question

我希望有人可以帮助我解决目前使用 Compact Framework.Net 2 SP 2 遇到的问题。

目前，我有一个带有一系列文本框的用户界面，每个文本框都显示数据库字段的内容。它们依次显示，并在表单右侧有一个滚动条。每个文本框都有一个设定的宽度，可能

我想根据每个文本框所包含的行数、字体大小和字体来调整每个文本框的高度，以避免在每个文本框上使用滚动条。

目前我可以在测试应用程序中执行此操作。

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截屏：

请参阅输出截图http://morrislgn.brinkster.net/SO/screenshot.jpg

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我的代码：

'Text used in this example:
'TextBox1qwertyuiop lkjhgfdsazxcvbnm1234567890 TextBo

'x1qwer tyuioplkjhgfdsazxcvb nm1234567890

'qwe
'End of exmaple text.

Me.Textbox2.Text = Me.Textbox1.Text

Dim pobjGraphic As Graphics = Me.Textbox2.Parent.CreateGraphics()
Dim pobjSize As SizeF

'Padding values:
Dim piTop As Int32 = 4 'top of text and top of textbox
Dim piBottom As Int32 = 3 'bottom of text and top of textbox

Dim piLines As Int32 = 0

'Based on the font size chosen by the user, create a font to perform the calculation with.
Dim piFontSize As Single = 10

If Me.CheckBox1.Checked.Equals(True) Then
    piFontSize = 6
ElseIf Me.CheckBox2.Checked.Equals(True) Then
    piFontSize = 8
ElseIf Me.CheckBox3.Checked.Equals(True) Then
    piFontSize = 12
Else
    piFontSize = 10
End If

Dim pobjFont As New Font("Tahoma", piFontSize, FontStyle.Regular)

'Calculate the height of one line.
pobjSize = pobjGraphic.MeasureString("HELLO WORLD", pobjFont)
'Value of pobjSize returned: {Width = 71.0 Height = 13.0}


'Calculate the number of lines          
Dim b As Bitmap
b = New Bitmap(1, 1, Imaging.PixelFormat.Format32bppRgb)

'Calculate the number of lines required to display the text properly based on the lenght of the text the width of the control.
'Length of text to show divide by the width of the textbox
piLines = Graphics.FromImage(b).MeasureString(Me.Textbox2.Text, pobjFont).Width / Me.Textbox2.Width
'Value of piLines returned: 2

If piLines = 0 Then
    piLines = 1
End If

'Calculate the size of the text to be displayed using the margins, height of one line and number of lines.
Me.Textbox2.Height = (pobjSize.Height * piLines) + piTop + piBottom
' value produced: 33 = (13 * 2) + 4 + 3
'set font of text box
Me.Textbox2.Font = pobjFont

最后，我知道这可以通过使用 p/invoke 调用 COREDLL.dll 来实现，但这样做会导致应用程序崩溃。

嗨伙计，

以下是请求的 pinvoke 代码：

    <Runtime.InteropServices.DllImport("coredll.dll")> _
Private Function SendMessage( _
    ByVal hwnd As IntPtr, ByVal msg As Integer, _
    ByVal wParam As Integer, ByVal lParam As Integer) As Integer
End Function

<Runtime.InteropServices.DllImport("coredll.dll")> _
Private Function GetCapture() As IntPtr
End Function

<Runtime.InteropServices.DllImport("coredll.dll")> _
Private Function ReleaseCapture() As Boolean
End Function

Public Function GetNumberOfLines(ByVal ptxtCountBox As TextBox) As Integer
    Try
        Dim hnd As IntPtr = New IntPtr

        ptxtCountBox.Capture = True

        ' Capture the textbox handle.
        hnd = GetCapture()
        ptxtCountBox.Capture = False

        ' Get the count of the lines in the box.
        Dim plCount As Integer = SendMessage(ptxtCountBox.Handle, EM_GETLINECOUNT, 0, 0)

        ' Count the number of return lines as we minus this from the total lines to take.
        plCount = plCount - (CharCount(ptxtCountBox.Text, vbCrLf, False))

        plCount += RemoveNonASCIIReturns(ptxtCountBox)

        ReleaseCapture()

        hnd = Nothing

        ' Return the line count.
        Return plCount
    Catch ex As Exception
        GenerateError(msCLASS_NAME, "GetNumberOfLines", ex.Message.ToString)
    End Try
End Function

谢谢，

莫里斯

Answer 1

我问过类似的问题，得到的回答是完全满意，我的关于这个问题的需求！请从我的问题检查stevo3000的回答： 的AutoSize在.NET Framework精简

他提到了一个刷卡只是完全固定我的问题这两个博客文章！ http://www.mobilepractices.com/2007/12/multi-线graphicsmeasurestring.html http://www.mobilepractices.com/2008/01/制作-多-measurestring-work.html

Answer 2

想我到的本底：

    Public Function GetNumberOfLines(ByVal pstext As String, ByVal pobjfont As Font, ByVal pobjDimensions As Size) As Decimal
    Dim pslines As String() = Nothing
    'Used to measure the string to be placed into the textbox
    Dim pobjBitMap As Bitmap = Nothing
    Dim pobjSize As SizeF = Nothing

    Try
        Dim psline As String = String.Empty
        Dim pilinecount As Decimal = 0.0
        'Spilt the text based on the number of lines breaks.
        pslines = pstext.Split(vbCrLf)
        For Each psline In pslines
            'Create a graphics image which is used to work out the width of the text.
            pobjBitMap = New Bitmap(1, 1, Imaging.PixelFormat.Format32bppRgb)
            pobjSize = Graphics.FromImage(pobjBitMap).MeasureString(psline, pobjfont)

            'If the width of the text is less than 1.0 then add one to the count. This would incidcate a line break.
            If pobjSize.Width < 1.0 Then
                pilinecount = pilinecount + 1
            Else
                'Based on the dimensions of the text, work out the number of lines. 0.5 is added to round the value to next whole number.
                pilinecount = pilinecount + (Round((pobjSize.Width / pobjDimensions.Width) + 0.5))
            End If
        Next

        'If the line count it less than 1 return one line.
        If pilinecount < 1.0 Then
            Return 1.0
        Else
            Return pilinecount
        End If
    Catch ex As Exception
        Return 1.0
    Finally
        If pslines IsNot Nothing Then
            Array.Clear(pslines, 0, pslines.Length - 1)
            pslines = Nothing
        End If
        If pobjBitMap IsNot Nothing Then
            pobjBitMap.Dispose()
        End If
    End Try
End Function

当然，它的一个黑客位，但它出现的那一刻好的工作！关于如何提高这任何意见或建议，都欢迎。

此外，关于在p /调用的东西，发现这个问题的根源，或者更确切地说，该溶液中。升级我的设备上安装.NET FX和似乎已经解决了这个问题。

由于

莫里斯

Answer 3

好吧，我会向您推荐一个合理且明智的解决方案。这是算法：

1. 使用 Label 控件作为参考。

2. 分配：• 文本框相对于标签的大小。• 文本框到标签的字体。• 标签的 Autosize 属性为 真的。• 文本框的标签的BorderStyle 属性。• Label 的MinimumSize 属性作为文本框的原始大小。• 标签的MaximumSize 属性为宽度-与原始高度相同，高度为原始高度的大倍数。

3. 将文本框的文本分配给标签的文本。

4. 现在：如果标签的prefferdheight-property> textbox的高度== true是时候增加文本框的高度并检查上述条件直到false。
5. 现在可以将标签丢弃。

我也在MSDN论坛上发布了类似的解决方案，也可以查看：[http://social.msdn.microsoft.com/Forums/en-US/winforms/thread/03fc8e75-fc13-417a-ad8c-d2b26a3a4dda][1]

问候。:)