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Saving PointF data in MSAccessI want to be able to save drawing path data in a database. If I store the Points array for each GraphicsPath I can then reproduce (in this case) filled polygons at run time. The user will create the polygons initially. The number of points in the polygons will vary so I only want to save this data in one field (rectangles would have been a lot easier). The only way I can think of doing this is by saving the points as a string in a Memo field; looping through all the points in the Array and using GetValue to add the points to the string e.g.: {x=369, y=89}{x=500, y=200}{x=700, y=300} To retrieve the polygon at the next run time then seems a bit messy i.e. to extract the points from the string and get them in the PointF format e.g.: PointArray(intZoneCount).SetValue(New PointF(369, 89), 0) (would be the first point) I can see how this can be done and I'm sure it will work but can anyone suggest a better way? or am I missing something blindingly obvious! Thanks in advance. How about using a binarywriter to write the values to a memorystream,
get the byte array from the stream and use the Convert.ToBase64String method to turn it into a string? Keith G wrote: Show quoteHide quote > VS2003 using VB.Net > > I want to be able to save drawing path data in a database. > If I store the Points array for each GraphicsPath I can then reproduce (in > this case) filled polygons at run time. The user will create the polygons > initially. > The number of points in the polygons will vary so I only want to save this > data in one field (rectangles would have been a lot easier). > > The only way I can think of doing this is by saving the points as a string > in a Memo field; looping through all the points in the Array and using > GetValue to add the points to the string e.g.: > {x=369, y=89}{x=500, y=200}{x=700, y=300} > > To retrieve the polygon at the next run time then seems a bit messy i.e. to > extract the points from the string and get them in the PointF format e.g.: > PointArray(intZoneCount).SetValue(New PointF(369, 89), 0) (would be the > first point) > I can see how this can be done and I'm sure it will work but can anyone > suggest a better way? or am I missing something blindingly obvious! > > Thanks in advance. Keith,
In addition to Goran. http://www.vb-tips.com/default.aspx?ID=5ad37c7b-3732-4558-8dd7-e68d238952a5 I hope this helps, Cor Show quoteHide quote "Keith G" <Kei***@discussions.microsoft.com> schreef in bericht news:6C60F4F6-4452-4F78-B571-1AF92B711D66@microsoft.com... > VS2003 using VB.Net > > I want to be able to save drawing path data in a database. > If I store the Points array for each GraphicsPath I can then reproduce (in > this case) filled polygons at run time. The user will create the polygons > initially. > The number of points in the polygons will vary so I only want to save this > data in one field (rectangles would have been a lot easier). > > The only way I can think of doing this is by saving the points as a string > in a Memo field; looping through all the points in the Array and using > GetValue to add the points to the string e.g.: > {x=369, y=89}{x=500, y=200}{x=700, y=300} > > To retrieve the polygon at the next run time then seems a bit messy i.e. > to > extract the points from the string and get them in the PointF format e.g.: > PointArray(intZoneCount).SetValue(New PointF(369, 89), 0) (would be the > first point) > I can see how this can be done and I'm sure it will work but can anyone > suggest a better way? or am I missing something blindingly obvious! > > Thanks in advance. Thanks Cor and Göran
I can see how the image data is converted into the Byte Array (and back) from the code example. Which is very neat. However, and this is the bit I'm struggling with, how do I save a GraphicsPath to a MemoryStream? Göran is suggesting using the BinaryWriter but how do I do that from a PointF array? The save and retrieve process to/from the database would therefore be: SAVE [GraphicsPath]->[BinaryWriter?]->[MemoryStream]->[Byte Array]->[ToBase64String] RETRIEVE [FromBase64String]->[Byte Array]->[MemoryStream]->[BinaryReader?]->[GraphicsPath] Show quoteHide quote "Cor Ligthert [MVP]" wrote: > Keith, > > In addition to Goran. > > http://www.vb-tips.com/default.aspx?ID=5ad37c7b-3732-4558-8dd7-e68d238952a5 > > I hope this helps, > > Cor > > "Keith G" <Kei***@discussions.microsoft.com> schreef in bericht > news:6C60F4F6-4452-4F78-B571-1AF92B711D66@microsoft.com... > > VS2003 using VB.Net > > > > I want to be able to save drawing path data in a database. > > If I store the Points array for each GraphicsPath I can then reproduce (in > > this case) filled polygons at run time. The user will create the polygons > > initially. > > The number of points in the polygons will vary so I only want to save this > > data in one field (rectangles would have been a lot easier). > > > > The only way I can think of doing this is by saving the points as a string > > in a Memo field; looping through all the points in the Array and using > > GetValue to add the points to the string e.g.: > > {x=369, y=89}{x=500, y=200}{x=700, y=300} > > > > To retrieve the polygon at the next run time then seems a bit messy i.e. > > to > > extract the points from the string and get them in the PointF format e.g.: > > PointArray(intZoneCount).SetValue(New PointF(369, 89), 0) (would be the > > first point) > > I can see how this can be done and I'm sure it will work but can anyone > > suggest a better way? or am I missing something blindingly obvious! > > > > Thanks in advance. > > > The PointsF struct contains two float values; X and Y. Loop through the
array of PointFs and write each pair of values to the BinaryWriter. To recreate the array you get two float values from the BinaryReader to create each PointF struct. As each float value is four bytes you can calculate the length of the PointF array by taking the length of the byte array and divide by eight. Keith G wrote: Show quoteHide quote > Thanks Cor and Göran > > I can see how the image data is converted into the Byte Array (and back) > from the code example. Which is very neat. > However, and this is the bit I'm struggling with, how do I save a > GraphicsPath to a MemoryStream? > Göran is suggesting using the BinaryWriter but how do I do that from a > PointF array? > > The save and retrieve process to/from the database would therefore be: > SAVE > [GraphicsPath]->[BinaryWriter?]->[MemoryStream]->[Byte > Array]->[ToBase64String] > RETRIEVE > [FromBase64String]->[Byte > Array]->[MemoryStream]->[BinaryReader?]->[GraphicsPath] > > > > > > "Cor Ligthert [MVP]" wrote: > >> Keith, >> >> In addition to Goran. >> >> http://www.vb-tips.com/default.aspx?ID=5ad37c7b-3732-4558-8dd7-e68d238952a5 >> >> I hope this helps, >> >> Cor >> >> "Keith G" <Kei***@discussions.microsoft.com> schreef in bericht >> news:6C60F4F6-4452-4F78-B571-1AF92B711D66@microsoft.com... >>> VS2003 using VB.Net >>> >>> I want to be able to save drawing path data in a database. >>> If I store the Points array for each GraphicsPath I can then reproduce (in >>> this case) filled polygons at run time. The user will create the polygons >>> initially. >>> The number of points in the polygons will vary so I only want to save this >>> data in one field (rectangles would have been a lot easier). >>> >>> The only way I can think of doing this is by saving the points as a string >>> in a Memo field; looping through all the points in the Array and using >>> GetValue to add the points to the string e.g.: >>> {x=369, y=89}{x=500, y=200}{x=700, y=300} >>> >>> To retrieve the polygon at the next run time then seems a bit messy i.e. >>> to >>> extract the points from the string and get them in the PointF format e.g.: >>> PointArray(intZoneCount).SetValue(New PointF(369, 89), 0) (would be the >>> first point) >>> I can see how this can be done and I'm sure it will work but can anyone >>> suggest a better way? or am I missing something blindingly obvious! >>> >>> Thanks in advance. >> >> I have now successfully saved and retrieved the PointF data using the
BinaryWriter and BinaryReader. For anybody else that might be interested the read and write loops respectively have ended up like this: ---------- For i = PointArray(intZoneCount).GetLowerBound(0) To PointArray(intZoneCount).GetUpperBound(0) pt = PointArray(intZoneCount).GetValue(i) bt = pt.X bw.Write(bt) bt = pt.Y bw.Write(bt) Next For i As Integer = 0 To intPts intX = br.ReadSingle intY = br.ReadSingle PointArray(intZoneCount).SetValue(New PointF(intX, intY), i) Next --------------- Thanks to Göran and Cor for your help. Regards.. Show quoteHide quote "Göran Andersson" wrote: > The PointsF struct contains two float values; X and Y. Loop through the > array of PointFs and write each pair of values to the BinaryWriter. > > To recreate the array you get two float values from the BinaryReader to > create each PointF struct. > > As each float value is four bytes you can calculate the length of the > PointF array by taking the length of the byte array and divide by eight. > > > Keith G wrote: > > Thanks Cor and Göran > > > > I can see how the image data is converted into the Byte Array (and back) > > from the code example. Which is very neat. > > However, and this is the bit I'm struggling with, how do I save a > > GraphicsPath to a MemoryStream? > > Göran is suggesting using the BinaryWriter but how do I do that from a > > PointF array? > > > > The save and retrieve process to/from the database would therefore be: > > SAVE > > [GraphicsPath]->[BinaryWriter?]->[MemoryStream]->[Byte > > Array]->[ToBase64String] > > RETRIEVE > > [FromBase64String]->[Byte > > Array]->[MemoryStream]->[BinaryReader?]->[GraphicsPath] > > > > > > > > > > > > "Cor Ligthert [MVP]" wrote: > > > >> Keith, > >> > >> In addition to Goran. > >> > >> http://www.vb-tips.com/default.aspx?ID=5ad37c7b-3732-4558-8dd7-e68d238952a5 > >> > >> I hope this helps, > >> > >> Cor > >> > >> "Keith G" <Kei***@discussions.microsoft.com> schreef in bericht > >> news:6C60F4F6-4452-4F78-B571-1AF92B711D66@microsoft.com... > >>> VS2003 using VB.Net > >>> > >>> I want to be able to save drawing path data in a database. > >>> If I store the Points array for each GraphicsPath I can then reproduce (in > >>> this case) filled polygons at run time. The user will create the polygons > >>> initially. > >>> The number of points in the polygons will vary so I only want to save this > >>> data in one field (rectangles would have been a lot easier). > >>> > >>> The only way I can think of doing this is by saving the points as a string > >>> in a Memo field; looping through all the points in the Array and using > >>> GetValue to add the points to the string e.g.: > >>> {x=369, y=89}{x=500, y=200}{x=700, y=300} > >>> > >>> To retrieve the polygon at the next run time then seems a bit messy i.e. > >>> to > >>> extract the points from the string and get them in the PointF format e.g.: > >>> PointArray(intZoneCount).SetValue(New PointF(369, 89), 0) (would be the > >>> first point) > >>> I can see how this can be done and I'm sure it will work but can anyone > >>> suggest a better way? or am I missing something blindingly obvious! > >>> > >>> Thanks in advance. > >> > >> > 
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