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RowCursor / BLOB

LaurentiuIchim2

Hello for all,

I have a Standalone Table with Binary Large Object (BLOB) field. Into BLOB field of the Table are various documents (Image, Excel Document PDF Document and so on).

I need to programmatically get this document and work it using Row Cursor.

How can I get the MemoryStream from the Row object?

Thank you in advance,

Laurentiu

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Anonymous User

I'll get that snippet in for blobs.

The raster field isn't supported in the same way currently. Its on the list.

GKmieliauskas

Hi Sean,

One more question. Is it possible to read/write from/to Raster type field? If yes- how?

GKmieliauskas

Thank you Sean.

I would be nice to see that information in Snippets and API reference

Anonymous User

You can now do this with either the Inspector class within an EditOperation:

      <SPAN class="comment token">//Run on MCT</SPAN>
      QueuedTask<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Run</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>
      <SPAN class="punctuation token">{</SPAN>
        <SPAN class="comment token">//get selected feature into inspector</SPAN>
        <SPAN class="keyword token">var</SPAN> selectedFeatures <SPAN class="operator token">=</SPAN> MapView<SPAN class="punctuation token">.</SPAN>Active<SPAN class="punctuation token">.</SPAN>Map<SPAN class="punctuation token">.</SPAN><SPAN class="token function">GetSelection</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        <SPAN class="keyword token">var</SPAN> insp <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">Inspector</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        insp<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Load</SPAN><SPAN class="punctuation token">(</SPAN>selectedFeatures<SPAN class="punctuation token">.</SPAN>Keys<SPAN class="punctuation token">.</SPAN><SPAN class="token function">First</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">,</SPAN> selectedFeatures<SPAN class="punctuation token">.</SPAN>Values<SPAN class="punctuation token">.</SPAN><SPAN class="token function">First</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

        <SPAN class="comment token">//read file into memory stream</SPAN>
        <SPAN class="keyword token">var</SPAN> msr <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">MemoryStream</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        <SPAN class="keyword token">using</SPAN> <SPAN class="punctuation token">(</SPAN>FileStream file <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">FileStream</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">@"d:\me\images\Hydrant.jpg"</SPAN><SPAN class="punctuation token">,</SPAN> FileMode<SPAN class="punctuation token">.</SPAN>Open<SPAN class="punctuation token">,</SPAN> FileAccess<SPAN class="punctuation token">.</SPAN>Read<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
        <SPAN class="punctuation token">{</SPAN>
          file<SPAN class="punctuation token">.</SPAN><SPAN class="token function">CopyTo</SPAN><SPAN class="punctuation token">(</SPAN>msr<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        <SPAN class="punctuation token">}</SPAN>

        <SPAN class="comment token">//put the memory stream in the blob field</SPAN>
        <SPAN class="keyword token">var</SPAN> op <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">EditOperation</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        op<SPAN class="punctuation token">.</SPAN>Name <SPAN class="operator token">=</SPAN> <SPAN class="string token">"Blob Inspector"</SPAN><SPAN class="punctuation token">;</SPAN>
        insp<SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Image"</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> msr<SPAN class="punctuation token">;</SPAN>
        <SPAN class="comment token">//insp.ApplyAsync();</SPAN>
        op<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Modify</SPAN><SPAN class="punctuation token">(</SPAN>insp<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        op<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Execute</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

        <SPAN class="comment token">//read blob field and save to a file</SPAN>
        <SPAN class="comment token">//assume inspector has been loaded with a feature</SPAN>
        <SPAN class="keyword token">var</SPAN> msw <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">MemoryStream</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        msw <SPAN class="operator token">=</SPAN> insp<SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Image"</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="keyword token">as</SPAN> MemoryStream<SPAN class="punctuation token">;</SPAN>
        <SPAN class="keyword token">using</SPAN> <SPAN class="punctuation token">(</SPAN>FileStream file <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">FileStream</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">@"d:\temp\blob.jpg"</SPAN><SPAN class="punctuation token">,</SPAN> FileMode<SPAN class="punctuation token">.</SPAN>Create<SPAN class="punctuation token">,</SPAN> FileAccess<SPAN class="punctuation token">.</SPAN>Write<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
        <SPAN class="punctuation token">{</SPAN>
          msw<SPAN class="punctuation token">.</SPAN><SPAN class="token function">WriteTo</SPAN><SPAN class="punctuation token">(</SPAN>file<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        <SPAN class="punctuation token">}</SPAN>
      <SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

or with the row object in a rowcursor:

      QueuedTask<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Run</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN>
      <SPAN class="punctuation token">{</SPAN>
        <SPAN class="keyword token">var</SPAN> editOp <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">EditOperation</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
        editOp<SPAN class="punctuation token">.</SPAN>Name <SPAN class="operator token">=</SPAN> <SPAN class="string token">"Blob Cursor"</SPAN><SPAN class="punctuation token">;</SPAN>
        <SPAN class="keyword token">var</SPAN> featLayer1 <SPAN class="operator token">=</SPAN> MapView<SPAN class="punctuation token">.</SPAN>Active<SPAN class="punctuation token">.</SPAN>Map<SPAN class="punctuation token">.</SPAN><SPAN class="token function">FindLayers</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">"Hydrant"</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="token function">First</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN> <SPAN class="keyword token">as</SPAN> FeatureLayer<SPAN class="punctuation token">;</SPAN>

        editOp<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Callback</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">(</SPAN>context<SPAN class="punctuation token">)</SPAN> <SPAN class="operator token">=</SPAN><SPAN class="operator token">></SPAN> <SPAN class="punctuation token">{</SPAN>
          <SPAN class="keyword token">using</SPAN> <SPAN class="punctuation token">(</SPAN><SPAN class="keyword token">var</SPAN> rc <SPAN class="operator token">=</SPAN> featLayer1<SPAN class="punctuation token">.</SPAN><SPAN class="token function">GetTable</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="token function">Search</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="keyword token">null</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="keyword token">false</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
          <SPAN class="punctuation token">{</SPAN>
            <SPAN class="keyword token">while</SPAN> <SPAN class="punctuation token">(</SPAN>rc<SPAN class="punctuation token">.</SPAN><SPAN class="token function">MoveNext</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
            <SPAN class="punctuation token">{</SPAN>
              <SPAN class="comment token">//context.Invalidate(rc.Current);</SPAN>
              <SPAN class="comment token">//read file into memory stream</SPAN>
              <SPAN class="keyword token">var</SPAN> msr <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">MemoryStream</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
              <SPAN class="keyword token">using</SPAN> <SPAN class="punctuation token">(</SPAN>FileStream file <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">FileStream</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">@"d:\me\images\Hydrant.jpg"</SPAN><SPAN class="punctuation token">,</SPAN> FileMode<SPAN class="punctuation token">.</SPAN>Open<SPAN class="punctuation token">,</SPAN> FileAccess<SPAN class="punctuation token">.</SPAN>Read<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
              <SPAN class="punctuation token">{</SPAN>
                file<SPAN class="punctuation token">.</SPAN><SPAN class="token function">CopyTo</SPAN><SPAN class="punctuation token">(</SPAN>msr<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
              <SPAN class="punctuation token">}</SPAN>

              rc<SPAN class="punctuation token">.</SPAN>Current<SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Image"</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="operator token">=</SPAN> msr<SPAN class="punctuation token">;</SPAN>
              rc<SPAN class="punctuation token">.</SPAN>Current<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Store</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>

              <SPAN class="comment token">//read the blob field to a file</SPAN>
              <SPAN class="keyword token">var</SPAN> msw <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">MemoryStream</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
              msw <SPAN class="operator token">=</SPAN> rc<SPAN class="punctuation token">.</SPAN>Current<SPAN class="punctuation token">[</SPAN><SPAN class="string token">"Image"</SPAN><SPAN class="punctuation token">]</SPAN> <SPAN class="keyword token">as</SPAN> MemoryStream<SPAN class="punctuation token">;</SPAN>
              <SPAN class="keyword token">using</SPAN> <SPAN class="punctuation token">(</SPAN>FileStream file <SPAN class="operator token">=</SPAN> <SPAN class="keyword token">new</SPAN> <SPAN class="token class-name">FileStream</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="string token">@"d:\temp\blob.jpg"</SPAN><SPAN class="punctuation token">,</SPAN> FileMode<SPAN class="punctuation token">.</SPAN>Create<SPAN class="punctuation token">,</SPAN> FileAccess<SPAN class="punctuation token">.</SPAN>Write<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN>
              <SPAN class="punctuation token">{</SPAN>
                msw<SPAN class="punctuation token">.</SPAN><SPAN class="token function">WriteTo</SPAN><SPAN class="punctuation token">(</SPAN>file<SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
              <SPAN class="punctuation token">}</SPAN>

              <SPAN class="comment token">//context.Invalidate(rc.Current);</SPAN>
            <SPAN class="punctuation token">}</SPAN>
          <SPAN class="punctuation token">}</SPAN>

         <SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">,</SPAN> featLayer1<SPAN class="punctuation token">.</SPAN><SPAN class="token function">GetTable</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN> <SPAN class="comment token">//Pass as parameters the datasets </SPAN>
        editOp<SPAN class="punctuation token">.</SPAN><SPAN class="token function">Execute</SPAN><SPAN class="punctuation token">(</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN>
      <SPAN class="punctuation token">}</SPAN><SPAN class="punctuation token">)</SPAN><SPAN class="punctuation token">;</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

JayantaPoddar_0-1654880963598.png

GKmieliauskas

Hi Sreevatsa,

Do you have information about supporting reading and writing BLOB fields in ArcGIS Pro 2.3?

SreevatsaSreeraman

Hi Laurentiu,

As Max suggested, we don't have support for reading and editing BLOB fields yet. It has been scheduled for the next release.

As a workaround, could attachments be used to store binary data? We have support to store binary data by assigning MemoryStreams or obtaining MemoryStreams from the Attachement table. Please refer to How to create a memory stream and Adding Attachments for more information.

-Sree

MaxMax2

Hi Laurentiu,

Values of BLOB fields are returned as COM objects now, so it seems that support of BLOBs editing is not implemented in current version (1.4) of the ArcGIS Pro SDK. I hope ESRI team working on ArcGIS Pro SDK will pay attention to this bug.

Max

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