IsShowingPlaceholderText
StructuredDocumentTagRangeStart.IsShowingPlaceholderText property
指定是否应将此结构化文档标记的内容解释为包含 占位符文本（与结构化文档标记内的常规文本内容相反）。
如果设置为真的，打开此文档后应恢复此状态（显示占位符文本）。
public bool IsShowingPlaceholderText { get; set; }
例子
演示如何获取多节结构化文档标签的属性。
Document doc = new Document(MyDir + "Multi-section structured document tags.docx");
StructuredDocumentTagRangeStart rangeStartTag =
doc.GetChildNodes(NodeType.StructuredDocumentTagRangeStart, true)[0] as StructuredDocumentTagRangeStart;
StructuredDocumentTagRangeEnd rangeEndTag =
doc.GetChildNodes(NodeType.StructuredDocumentTagRangeEnd, true)[0] as StructuredDocumentTagRangeEnd;
Console.WriteLine("StructuredDocumentTagRangeStart values:");
Console.WriteLine($"\t|Id: {rangeStartTag.Id}");
Console.WriteLine($"\t|Title: {rangeStartTag.Title}");
Console.WriteLine($"\t|PlaceholderName: {rangeStartTag.PlaceholderName}");
Console.WriteLine($"\t|IsShowingPlaceholderText: {rangeStartTag.IsShowingPlaceholderText}");
Console.WriteLine($"\t|LockContentControl: {rangeStartTag.LockContentControl}");
Console.WriteLine($"\t|LockContents: {rangeStartTag.LockContents}");
Console.WriteLine($"\t|Level: {rangeStartTag.Level}");
Console.WriteLine($"\t|NodeType: {rangeStartTag.NodeType}");
Console.WriteLine($"\t|RangeEnd: {rangeStartTag.RangeEnd}");
Console.WriteLine($"\t|Color: {rangeStartTag.Color.ToArgb()}");
Console.WriteLine($"\t|SdtType: {rangeStartTag.SdtType}");
Console.WriteLine($"\t|FlatOpcContent: {rangeStartTag.WordOpenXML}");
Console.WriteLine($"\t|Tag: {rangeStartTag.Tag}\n");
Console.WriteLine("StructuredDocumentTagRangeEnd values:");
Console.WriteLine($"\t|Id: {rangeEndTag.Id}");
Console.WriteLine($"\t|NodeType: {rangeEndTag.NodeType}");
