Topic: Purging empty text object in VB.NET

[slappy]

Any thoughts?

Doing a symble check of:

Code: [Select]

String.Emptyon the contents doesn't seem to work.

Here is what I've tried

Code: [Select]

Dim txt As DBText = TryCast(tr.GetObject(id, OpenMode.ForRead), DBText)
If txt IsNot Nothing Then
   If txt.TextString.Trim() = String.Empty Then
      txt.UpgradeOpen()
      txt.[Erase]()
   End If
   Continue For
End If
Dim mTxt As MText = TryCast(tr.GetObject(id, OpenMode.ForRead), MText)
If mTxt IsNot Nothing Then
   Dim result As String = mTxt.Contents
   If result.Trim = String.Empty Then
      mTxt.UpgradeOpen()
      mTxt.[Erase]()
    End If
End If

Thanks

Chris

[Bryco]

if (string.IsNullOrEmpty(text.TextString.Trim()))   is this available in vb

[Jeff H]

Is there ever an instance or will AutoCad allow you to have an empty string

[slappy]

if (string.IsNullOrEmpty(text.TextString.Trim()))   is this available in vb

It is!  I'll see if that works.

[slappy]

Is there ever an instance or will AutoCad allow you to have an empty string

You would think...

However, there is the option to purge it and it tells me there is one and that it is removed during a manual "-purge".  Draw your own conclusions.   

[David Hall]

Is there ever an instance or will AutoCad allow you to have an empty string

If you have one of those "power" users that erase text by replacing the contents with a single space, you can get these.

[Kerry]

[offTopic]

I'll have to stop looking at VB.net code ;
a language that has the same operator for Assignment and Logical Comparison gives me a headache.

[/backToIt]

[Jeff H]

I just did the empty space thing and it was flagged to be erased

[kaefer]

Is there ever an instance or will AutoCad allow you to have an empty string

If you have one of those "power" users that erase text by replacing the contents with a single space, you can get these.

Why, can't you screw up automagically all by yourself?

Code: [Select]

    let db = acApp.DocumentManager.MdiActiveDocument.Database
    use tr = db.TransactionManager.StartTransaction()
    let btr = db.CurrentSpaceId.GetObject OpenMode.ForWrite :?> BlockTableRecord
    // Empty text
    let tx = new DBText()
    btr.AppendEntity tx |> ignore
    tr.AddNewlyCreatedDBObject(tx, true)
    // Zero length geometry
    let pl = new Polyline()
    btr.AppendEntity pl |> ignore
    tr.AddNewlyCreatedDBObject(pl, true)
    tr.Commit()

[gile]

Hi,

With mtexts, you have to consider formated strings: "{\fArial|b0|i0|c0|p34; }" is an empty mtext content.

The way I deal with this here.

Code: [Select]

// ...
DBText txt = tr.GetObject(id, OpenMode.ForRead) as DBText;
                                if (txt != null)
                                {
                                    if (txt.TextString.Trim() == string.Empty)
                                    {
                                        txt.UpgradeOpen();
                                        txt.Erase();
                                    }
                                    continue;
                                }
                                MText mTxt = tr.GetObject(id, OpenMode.ForRead) as MText;
                                if (mTxt != null && UnFormatMtext(mTxt.Contents).Trim() == string.Empty)
                                {
                                    mTxt.UpgradeOpen();
                                    mTxt.Erase();
                                }
//...

 private string UnFormatMtext(string str)
        {
            StringBuilder sb = new StringBuilder(str);
            string[] patterns = new string[14] {
                "\\A", "\\T", "\\C", "\\Q", "\\W", "\\H", "\\F",
                "\\a", "\\t", "\\c", "\\q", "\\w", "\\h", "\\f"};
            while (sb.ToString().Contains(MText.BlockBegin))
            {
                int begin = sb.ToString().IndexOf(MText.BlockBegin);
                int end = sb.ToString().IndexOf(MText.BlockEnd, begin);
                StringBuilder sub =
                    new StringBuilder(sb.ToString().Substring(begin + 1, end - begin - 1));
                foreach (string pat in patterns)
                {
                    while (sub.ToString().Contains(pat))
                    {
                        int n = sub.ToString().IndexOf(pat);
                        sub.Remove(n, sub.ToString().IndexOf(';', n) - n + 1);
                    }
                }
                sb.Remove(begin, end - begin + 1);
                sb.Insert(begin, sub.ToString());
            }
            int i = 0;
            while ((i = sb.ToString().IndexOf("\\S", i)) != -1)
            {
                int j = sb.ToString().IndexOf(';', i);
                if (j != -1)
                {
                    int k = sb.ToString().IndexOf('/', i);
                    if (k != -1 && k < j)
                    {
                        sb.Remove(j, 1); ;
                        sb.Remove(i, 2);
                        continue;
                    }
                    k = sb.ToString().IndexOf('#', i);
                    if (k != -1 && k < j)
                    {
                        sb.Remove(j, 1);
                        sb.Remove(k, 1);
                        sb.Insert(k, '/');
                        sb.Remove(i, 2);
                        continue;
                    }
                    k = sb.ToString().IndexOf('^', i);
                    if (k != -1 && k < j)
                    {
                        sb.Remove(j, 1);
                        sb.Remove(k, 1);
                        sb.Insert(k, '/');
                        sb.Remove(i, 2);
                        continue;
                    }
                    i++;
                }
            }
            patterns = new string[7] { "\\P", "\\p", "\\L", "\\p", "\\O", "\\o", "\\~" };
            foreach (string pat in patterns)
            {
                sb.Replace(pat, string.Empty);
            }
            return sb.ToString();
        }

[Kerry]

gile,

Have you played with

MtextFragment class
and
ExplodeFragements() method in the MText Class  to strip the formatting ??

I recall Tony posted a link(on the newsgroup) to a sample on his site.

[Jeff H]

This erased them

Code: [Select]

Dim pad As String = ""
    If txt.TextString = pad.PadRight(txt.TextString.Count) Then
        txt.UpgradeOpen()
        txt.Erase()
    End If


[Jeff H]

It did not work for Mtext you could use what Kerry what mentioned
Or maybe do a string.split and use "\" as the dilimter and check for <=1

[gile]

Thanks Kerry.

I didn't play with ExplodeFragments() before, I'm glad having learned something new this morning.

Here's a new example, inspired by Tony's sample.

Code: [Select]

// ...
DBText txt = tr.GetObject(id, OpenMode.ForRead) as DBText;
if (txt != null)
{
    if (txt.TextString.Trim() == string.Empty)
    {
        txt.UpgradeOpen();
        txt.Erase();
    }
    continue;
}
MText mTxt = tr.GetObject(id, OpenMode.ForRead) as MText;
if (mTxt != null && GetStripedMtextContents(mTxt).Trim() == string.Empty)
{
     mTxt.UpgradeOpen();
     mTxt.Erase();
}
//...

private string m_str;

private string GetStripedMtextContents(MText mt)
{
     m_str = string.Empty;
     mt.ExplodeFragments(new MTextFragmentCallback(FragmentCallback));
     return m_str;
 }

private MTextFragmentCallbackStatus FragmentCallback(MTextFragment fragment, object obj)
{
     m_str += fragment.Text;
     return MTextFragmentCallbackStatus.Continue;
}