插入Checkboxes、文本输入或图像

合并引擎将文档作为输入，在其中查找MERGEFIELD字段，并将其替换为从数据源获取的数据。 通常，插入纯文本和HTML，但Aspose.Words用户也可以生成处理Mail Merge字段更不寻常的情况的文档。

强大的Aspose.Words功能允许您扩展Mail Merge进程:

• 在mail merge期间将checkboxes和文本输入表单字段插入文档
• 从任何自定义存储（文件，BLOB字段等）插入图像。)

在Mail Merge期间插入Checkboxes和文本输入

有时需要执行Mail Merge操作，以便在合并字段中替换的不是文本，而是checkbox或文本输入字段。 尽管这不是最常见的情况，但它对于某些任务来说非常方便。

下面的Word文档截图显示了一个包含合并字段的模板:

下面Word文档的屏幕截图显示了已经生成的文档:

请注意，某些字段被替换为纯文本，某些字段被替换为checkbox表单字段，Subject字段被替换为文本输入字段。

下面的代码示例演示如何在mail merge期间将checkboxes和输入文本字段插入到文档中:

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
Document doc = new Document(MyDir + "Mail merge destinations - Fax.docx");

// Setup mail merge event handler to do the custom work.
doc.MailMerge.FieldMergingCallback = new HandleMergeField();
// Trim trailing and leading whitespaces mail merge values.
doc.MailMerge.TrimWhitespaces = false;

string[] fieldNames = {
    "RecipientName", "SenderName", "FaxNumber", "PhoneNumber",
    "Subject", "Body", "Urgent", "ForReview", "PleaseComment"
};

object[] fieldValues = {
    "Josh", "Jenny", "123456789", "", "Hello",
    "<b>HTML Body Test message 1</b>", true, false, true
};

doc.MailMerge.Execute(fieldNames, fieldValues);

doc.Save(ArtifactsDir + "WorkingWithFields.MailMergeFormFields.docx");

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
private class HandleMergeField : IFieldMergingCallback
{
    /// <summary>
    /// This handler is called for every mail merge field found in the document,
    /// for every record found in the data source.
    /// </summary>
    void IFieldMergingCallback.FieldMerging(FieldMergingArgs e)
    {
        if (mBuilder == null)
            mBuilder = new DocumentBuilder(e.Document);

        // We decided that we want all boolean values to be output as check box form fields.
        if (e.FieldValue is bool)
        {
            // Move the "cursor" to the current merge field.
            mBuilder.MoveToMergeField(e.FieldName);

            string checkBoxName = $"{e.FieldName}{e.RecordIndex}";

            mBuilder.InsertCheckBox(checkBoxName, (bool) e.FieldValue, 0);

            return;
        }

        switch (e.FieldName)
        {
            case "Body":
                mBuilder.MoveToMergeField(e.FieldName);
                mBuilder.InsertHtml((string) e.FieldValue);
                break;
            case "Subject":
            {
                mBuilder.MoveToMergeField(e.FieldName);
                string textInputName = $"{e.FieldName}{e.RecordIndex}";
                mBuilder.InsertTextInput(textInputName, TextFormFieldType.Regular, "", (string) e.FieldValue, 0);
                break;
            }
        }
    }

    void IFieldMergingCallback.ImageFieldMerging(ImageFieldMergingArgs args)
    {
        args.ImageFileName = "Image.png";
        args.ImageWidth.Value = 200;
        args.ImageHeight = new MergeFieldImageDimension(200, MergeFieldImageDimensionUnit.Percent);
    }

    private DocumentBuilder mBuilder;
}

在Mail Merge期间插入图像

执行Mail Merge操作时，可以使用特殊的图像Mail Merge字段将数据库中的图像插入到文档中。 ImageMail Merge字段是一个名为Image:MyFieldName的合并字段。

从数据库中插入图像

在mail merge期间，当在文档中遇到图像Mail Merge字段时，会触发FieldMergingCallback事件。 您可以响应此事件以将文件名、流或图像对象返回到Mail Merge引擎，以便将其插入到文档中。

下面的代码示例演示如何将数据库BLOB字段中存储的图像插入到报表中:

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
Document doc = new Document(MyDir + "Mail merge destination - Northwind employees.docx");

doc.MailMerge.FieldMergingCallback = new HandleMergeImageFieldFromBlob();

string connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + DatabaseDir + "Northwind.accdb";
OleDbConnection conn = new OleDbConnection(connString);
conn.Open();

OleDbCommand cmd = new OleDbCommand("SELECT * FROM Employees", conn);
IDataReader dataReader = cmd.ExecuteReader();

doc.MailMerge.ExecuteWithRegions(dataReader, "Employees");

conn.Close();
            
doc.Save(ArtifactsDir + "WorkingWithFields.MailMergeImageFromBlob.docx");

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
public class HandleMergeImageFieldFromBlob : IFieldMergingCallback
{
    void IFieldMergingCallback.FieldMerging(FieldMergingArgs args)
    {
        // Do nothing.
    }

    /// <summary>
    /// This is called when mail merge engine encounters Image:XXX merge field in the document.
    /// You have a chance to return an Image object, file name, or a stream that contains the image.
    /// </summary>
    void IFieldMergingCallback.ImageFieldMerging(ImageFieldMergingArgs e)
    {
        // The field value is a byte array, just cast it and create a stream on it.
        MemoryStream imageStream = new MemoryStream((byte[]) e.FieldValue);
        // Now the mail merge engine will retrieve the image from the stream.
        e.ImageStream = imageStream;
    }
}

在Mail Merge期间设置图像属性

在合并图像合并字段时，有时可能需要控制各种图像属性，例如WrapType。

目前，使用ImageFieldMergingArgs只能分别设置图像宽度或高度属性。 为了解决这个问题，Aspose.Words提供了Shape属性，这有助于完全控制插入的图像或任何其他形状。

下面的代码示例演示如何设置各种图像属性:

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);

builder.Writeln("{{#foreach example}}");
builder.Writeln("{{Image(126pt;126pt):stempel}}");
builder.Writeln("{{/foreach example}}");

doc.MailMerge.UseNonMergeFields = true;
doc.MailMerge.TrimWhitespaces = true;
doc.MailMerge.UseWholeParagraphAsRegion = false;
doc.MailMerge.CleanupOptions = MailMergeCleanupOptions.RemoveEmptyTableRows
        | MailMergeCleanupOptions.RemoveContainingFields
        | MailMergeCleanupOptions.RemoveUnusedRegions
        | MailMergeCleanupOptions.RemoveUnusedFields;

doc.MailMerge.FieldMergingCallback = new ImageFieldMergingHandler();
doc.MailMerge.ExecuteWithRegions(new DataSourceRoot());

doc.Save(ArtifactsDir + "WorkingWithFields.MailMergeImageField.docx");

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
private class ImageFieldMergingHandler : IFieldMergingCallback
{
    void IFieldMergingCallback.FieldMerging(FieldMergingArgs args)
    {
        //  Implementation is not required.
    }

    void IFieldMergingCallback.ImageFieldMerging(ImageFieldMergingArgs args)
    {
        Shape shape = new Shape(args.Document, ShapeType.Image)
        {
            Width = 126, Height = 126, WrapType = WrapType.Square
        };

        shape.ImageData.SetImage(MyDir + "Mail merge image.png");

        args.Shape = shape;
    }
}

// For complete examples and data files, please go to https://github.com/aspose-words/Aspose.Words-for-.NET.git.
public class DataSourceRoot : IMailMergeDataSourceRoot
{
    public IMailMergeDataSource GetDataSource(string s)
    {
        return new DataSource();
    }

    private class DataSource : IMailMergeDataSource
    {
        private bool next = true;

        string IMailMergeDataSource.TableName => TableName();

        private string TableName()
        {
            return "example";
        }

        public bool MoveNext()
        {
            bool result = next;
            next = false;
            return result;
        }

        public IMailMergeDataSource GetChildDataSource(string s)
        {
            return null;
        }

        public bool GetValue(string fieldName, out object fieldValue)
        {
            fieldValue = null;
            return false;
        }
    }
}