hi.
ive been searching for help with storing images in access. after much
hunting i found this bit of code that Cor Ligthert put up on another forum.
but when i try to update to the dataset, i get this error: system.argument.
exception in system.data.dll, cannot change data type of a column once it has
data.
for one thing my column is empty, for another, i get that message even when i
select "upload to dataset" without first selecting an image.
can someone please help?
\\\it needs a picturebox and four buttons on a page. Private abyt() As Byte Private fo As New OpenFileDialog Private sf As New SaveFileDialog
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 'Reading a picture and put it in a bytearray If fo.ShowDialog = DialogResult.OK Then Dim fs As New IO.FileStream(fo.FileName, _ IO.FileMode.Open) Dim br As New IO.BinaryReader(fs) abyt = br.ReadBytes(CInt(fs.Length)) br.Close() 'just to show the sample without a fileread error Dim ms As New IO.MemoryStream(abyt) Me.PictureBox1.Image = Image.FromStream(ms) End If End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal _ e As System.EventArgs) Handles Button2.Click 'writing a picture from a bytearray If sf.ShowDialog = DialogResult.OK Then Dim fs As New IO.FileStream(sf.FileName, _ IO.FileMode.CreateNew) Dim bw As New IO.BinaryWriter(fs) bw.Write(abyt) bw.Close() End If End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal _ e As System.EventArgs) Handles Button3.Click 'writing a bytearray to a dataset Dim ds As New DataSet ds.Tables.Add(New DataTable("Photo")) ds.Tables(0).Columns.Add(New DataColumn("Sample")) ds.Tables(0).Columns(0).DataType = System.Type.GetType("System.Byte[]") ds.Tables(0).Rows.Add(ds.Tables(0).NewRow) ds.Tables(0).Rows(0)(0) = abyt Dim sf As New SaveFileDialog If sf.ShowDialog = DialogResult.OK Then ds.WriteXml(sf.FileName, XmlWriteMode.WriteSchema) End If End Sub
Private Sub Button4_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles Button4.Click 'reading a picture from a dataset Dim ds As New DataSet If fo.ShowDialog = DialogResult.OK Then ds.ReadXml(fo.FileName) End If abyt = CType(ds.Tables(0).Rows(0)(0), Byte()) Dim ms As New IO.MemoryStream(abyt) Me.PictureBox1.Image = Image.FromStream(ms) End Sub ///
Cor
thanks.
--
Message posted via http://www.dotnetmonster.com 3 5345
Anewbie,
I tested the sample again and could not find really errors. (withouth a part
that could go wrong in wrong sequence (try to read a dataset and than
abording), I changed that). http://www.vb-tips.com/default.aspx?...6-38b5a2f7fdf0
However I have the idea that your problem has not to do with this, but just
with reading and writing a dataset to/from an access database. Can you
explain it a little bit more.
Cor
However in my idea
"anewbie @ VB.NET via DotNetMonster.com" <u16975@uwe> schreef in bericht
news:5b8e90a30b2ec@uwe... hi.
ive been searching for help with storing images in access. after much hunting i found this bit of code that Cor Ligthert put up on another forum. but when i try to update to the dataset, i get this error: system.argument. exception in system.data.dll, cannot change data type of a column once it has data.
for one thing my column is empty, for another, i get that message even when i select "upload to dataset" without first selecting an image.
can someone please help?
\\\it needs a picturebox and four buttons on a page. Private abyt() As Byte Private fo As New OpenFileDialog Private sf As New SaveFileDialog
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 'Reading a picture and put it in a bytearray If fo.ShowDialog = DialogResult.OK Then Dim fs As New IO.FileStream(fo.FileName, _ IO.FileMode.Open) Dim br As New IO.BinaryReader(fs) abyt = br.ReadBytes(CInt(fs.Length)) br.Close() 'just to show the sample without a fileread error Dim ms As New IO.MemoryStream(abyt) Me.PictureBox1.Image = Image.FromStream(ms) End If End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal _ e As System.EventArgs) Handles Button2.Click 'writing a picture from a bytearray If sf.ShowDialog = DialogResult.OK Then Dim fs As New IO.FileStream(sf.FileName, _ IO.FileMode.CreateNew) Dim bw As New IO.BinaryWriter(fs) bw.Write(abyt) bw.Close() End If End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal _ e As System.EventArgs) Handles Button3.Click 'writing a bytearray to a dataset Dim ds As New DataSet ds.Tables.Add(New DataTable("Photo")) ds.Tables(0).Columns.Add(New DataColumn("Sample")) ds.Tables(0).Columns(0).DataType = System.Type.GetType("System.Byte[]") ds.Tables(0).Rows.Add(ds.Tables(0).NewRow) ds.Tables(0).Rows(0)(0) = abyt Dim sf As New SaveFileDialog If sf.ShowDialog = DialogResult.OK Then ds.WriteXml(sf.FileName, XmlWriteMode.WriteSchema) End If End Sub
Private Sub Button4_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles Button4.Click 'reading a picture from a dataset Dim ds As New DataSet If fo.ShowDialog = DialogResult.OK Then ds.ReadXml(fo.FileName) End If abyt = CType(ds.Tables(0).Rows(0)(0), Byte()) Dim ms As New IO.MemoryStream(abyt) Me.PictureBox1.Image = Image.FromStream(ms) End Sub ///
Cor
thanks.
-- Message posted via http://www.dotnetmonster.com
hi! thanks for the help... i dont understand - why am i alone getting that
error! hmm. strange. anyhow, my problem is this: im creating a database for
managing personnel records, and id like to have the employees passport sized
photograph displayed in the main form.
im able to store the file path properly, but i dont understand this image
memory streaming bit. i was told theres an image load option in vb... would i
be able to use that to upload, save and display my images?
thanks
--
Message posted via DotNetMonster.com http://www.dotnetmonster.com/Uwe/For...b-net/200602/1
Anewbie,
I thought that the most problems were with Access in this the type of the
datafield.
I thought it was something as binary.
Cor This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
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