Insert image from databse into MailMerge field in Word document

[PeterMardell]

Hi
I’m trying to insert an image from a database into a word doc using mailmerge and I’m getting an error
Buffer cannot be null.
Parameter name: buffer

This is the code…

SqlCommand cmd = new SqlCommand("up_SelectAdvisorDetails", connStr);
cmd.CommandType = System.Data.CommandType.StoredProcedure;
string pUserName = Convert.ToString(Session["UserName"]);
cmd.Parameters.AddWithValue("@UserName", pUserName);

connStr.Open();

SqlDataReader dataReader = cmd.ExecuteReader();
while (dataReader.Read())
{
    // Set up the event handler for image fields.
    doc.MailMerge.FieldMergingCallback = new HandleMergeImageFieldFromBlob();

    if (!dataReader["SignatureImage"].Equals(DBNull.Value))
    {
        doc.MailMerge.Execute(new string[]
            {
                "AdviserSignature"
            },
            new object[]
            {
                dataReader["SignatureImage"]
            });
    }

    if (!dataReader["LogoImage"].Equals(DBNull.Value))
    {
        doc.MailMerge.Execute(new string[]
            {
                "AdviserLogo"
            },
            new object[]
            {
                dataReader["LogoImage"]
            });
    }

}
dataReader.Close();

Here’ s the merge field in the document…

«Image:AdviserLogo»

I’ve downloaded the lastest version today. Can you help me?
thanks
Peter

[AndreyN]

Hello
Thanks for your request. Please see the following link to learn how to insert images from a Data Base during MailMerge:
https://docs.aspose.com/words/net/types-of-mail-merge-operations/
Hope this helps.
Best regards,

[PeterMardell]

yes, I have read that article before posting my problem.

do you have any other examples

[alexey.noskov]

Hi
Thanks for your request. such exception can occur when you try to create a MemoryStream and pass null as parameter:

byte[] buff = null;
MemoryStream ms = new MemoryStream(buff);

So, in your implementation of IFieldMergingCallback, you should make sure buffer is not null.
Best regards,

[PeterMardell]

wow, you right,
who would have thought that the error message
Buffer cannot be null.
Parameter name: buffer

would be raised if you pass null as parameter?
absolute genius.

[alexey.noskov]

Hi Peter,
It is perfect that you managed to resolve the problem. Please feel free to ask in case of any issues, we are always glad to help you.
Best regards,

[PeterMardell]

Hi
I haven’t solved the problem.

I’m not a C# programmer, can you provide the code to do the check for a null buffer?

Why would the buffer be null if the sql is returning the images from the database?

Can you give me an example that doesn’t use a datatable?

thanks
Peter

[alexey.noskov]

Hi Peter,
Thanks for your request.

1. I supposed you are using C# because the code example provided in your first post is written in C#. Anyways, here is simple code example that check for nulls in IFieldMergingCallback:

[Test]
public void Test001()
{
    // Open template.
    Document doc = new Document(@"Test001\in.doc");
    // Specify field merging callback.
    doc.MailMerge.FieldMergingCallback = new FieldMergingCallback();
    // Execute mail merge.
    doc.MailMerge.Execute(new string[]
    {
        "myimage",
        "nullimage"
    }, new object[]
    {
        File.ReadAllBytes(@"Test001\test.png"), null
    });
    // Save output.
    doc.Save(@"Test001\out.doc");
}
private class FieldMergingCallback: IFieldMergingCallback
{
    public void FieldMerging(FieldMergingArgs args)
    {
        // do nothing.
    }
    void IFieldMergingCallback.ImageFieldMerging(ImageFieldMergingArgs args)
    {
        if (args.FieldValue != null)
        {
            byte[] imageBytes = (byte[]) args.FieldValue;
            args.ImageStream = new MemoryStream(imageBytes);
        }
    }
}

2. Unfortunately, I cannot answer this question because i did not see your database. Maybe there are records without image bytes.
3. See the example above.

Best regards,