C# AutoCAD替换块

要在C#中替换AutoCAD中的块，您可以使用以下代码：

// 定义一个用于替换块的方法
public static void ReplaceBlock(Database db, string blockName, ObjectId newBlockId)
{
    // 打开块表
    BlockTable bt = db.BlockTableId.GetObject(OpenMode.ForRead) as BlockTable;

    if (bt.Has(blockName)) // 检查块表中是否有该块
    {
        // 打开块表记录
        BlockTableRecord btr = bt[blockName].GetObject(OpenMode.ForWrite) as BlockTableRecord;

        // 遍历块表记录中的所有块参照
        foreach (ObjectId id in btr)
        {
            Entity ent = id.GetObject(OpenMode.ForRead) as Entity;
            if (ent.BlockId == btr.ObjectId && ent is BlockReference) // 检查是否为块参照
            {
                BlockReference br = ent as BlockReference;
                if (br.Name == blockName) // 检查块参照是否为要替换的块
                {
                    // 创建新的块参照，并将其属性与旧的块参照相同
                    BlockReference newBr = new BlockReference(br.Position, newBlockId);
                    newBr.CopyFrom(br);

                    // 将新的块参照添加到块表记录中
                    btr.AppendEntity(newBr);
                    db.TransactionManager.AddNewlyCreatedDBObject(newBr, true);

                    // 删除旧的块参照
                    br.Erase();
                }
            }
        }
    }
}

使用方法：

// 打开AutoCAD文档
Document doc = Application.DocumentManager.Open(fileName, false);

// 开启事务
using (Transaction tr = doc.TransactionManager.StartTransaction())
{
    // 获取数据库
    Database db = doc.Database;

    // 获取要替换的块和新的块的ObjectId
    string oldBlockName = "OldBlockName";
    string newBlockName = "NewBlockName";
    ObjectId oldBlockId = SymbolUtilityServices.GetBlockObjectIdFromName(oldBlockName, true);
    ObjectId newBlockId = SymbolUtilityServices.GetBlockObjectIdFromName(newBlockName, true);

    // 替换块
    ReplaceBlock(db, oldBlockName, newBlockId);

    // 提交事务
    tr.Commit();
}

// 保存并关闭文档
doc.CloseAndSave(fileName);