C#编写Autodesk Inventor插件时CreateDescription方法字符串为空求助

嘿，我一眼就揪出问题所在了——你在buttonOK_Click和buttonApply_Click方法里都调用了InitializeComponent()！

这个方法是Windows Forms用来初始化所有窗体控件的核心方法，只应该在窗体构造函数里调用一次。每次运行它，你的下拉框（comboBoxPrefix、comboBoxDescription1等）和文本框（textBoxFreeText）都会被强制重置为设计时的初始状态，用户之前选择或输入的内容会被彻底清空，这就导致CreateDescription()根本拿不到任何有效内容。

解决方案： #

第一步就是把两个按钮事件里的InitializeComponent()删掉！另外我还帮你优化了代码——把重复获取Inventor应用和文档对象的逻辑提取为类成员变量，避免重复代码，提升性能。

修改后的完整代码示例：

using System;
using System.Windows.Forms;
using Inventor;
using System.Runtime.InteropServices;

namespace XXX_Property_Editor
{
    public partial class FormPropertyEditor : Form
    {
        // 提取为类成员变量，避免重复创建
        private Inventor.Application _invApp;
        private Document _activeDoc;

        public FormPropertyEditor()
        {
            InitializeComponent();
            string progId = "Inventor.Application";
            _invApp = (Inventor.Application)Marshal.GetActiveObject(progId);
            _activeDoc = (Document)_invApp.ActiveDocument;
        }

        #region Buttons
        private void buttonOK_Click(object sender, EventArgs e)
        {
            string userName = System.Environment.UserName;
            string txtDescription = CreateDescription();
            
            SetProperty setProperty = new SetProperty();
            setProperty.EditDesignTrackingProperty("Description", txtDescription, _activeDoc);
            setProperty.EditSummaryProperty("Title", txtDescription, _activeDoc);
            setProperty.EditDocumentSummaryProperty("Company", "MHS", _activeDoc);
            setProperty.EditSummaryProperty("Author", userName, _activeDoc);
            setProperty.EditDesignTrackingProperty("Designer", userName, _activeDoc);
            setProperty.EditDesignTrackingProperty("Engineer", userName, _activeDoc);
            
            this.Close();
        }

        private void buttonCancel_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void buttonApply_Click(object sender, EventArgs e)
        {
            string userName = System.Environment.UserName;
            string txtDescription = CreateDescription();
            MessageBox.Show(txtDescription);
            
            SetProperty setProperty = new SetProperty();
            setProperty.EditDesignTrackingProperty("Description", txtDescription, _activeDoc);
            setProperty.EditSummaryProperty("Title", txtDescription, _activeDoc);
            setProperty.EditDocumentSummaryProperty("Company", "XXX", _activeDoc);
            setProperty.EditSummaryProperty("Author", userName, _activeDoc);
            setProperty.EditDesignTrackingProperty("Designer", userName, _activeDoc);
            setProperty.EditDesignTrackingProperty("Engineer", userName, _activeDoc);
        }
        #endregion

        #region Description
        private void comboBoxPrefix_SelectionChangeCommitted(object sender, EventArgs e)
        {
            this.labelDescription.Text = CreateDescription();
        }

        private void comboBoxDescription1_SelectionChangeCommitted(object sender, EventArgs e)
        {
            this.labelDescription.Text = CreateDescription();
        }

        private void comboBoxDescription2_SelectedIndexChanged(object sender, EventArgs e)
        {
            this.labelDescription.Text = CreateDescription();
        }

        private void textBoxFreeText_TextChanged(object sender, EventArgs e)
        {
            this.labelDescription.Text = CreateDescription();
        }

        private string CreateDescription()
        {
            string txtPrefix = this.comboBoxPrefix.GetItemText(comboBoxPrefix.SelectedItem);
            string txtDescription1 = this.comboBoxDescription1.GetItemText(comboBoxDescription1.SelectedItem);
            string txtDescription2 = this.comboBoxDescription2.GetItemText(comboBoxDescription2.SelectedItem);
            string txtFree = this.textBoxFreeText.Text;
            return $"{txtPrefix}_{txtDescription1} {txtDescription2} {txtFree}";
        }
        #endregion
    }
}

额外小贴士： #

1. 牢记InitializeComponent()的作用：它是用来加载窗体设计器里的控件布局和初始值的，运行时绝对不能重复调用，否则会直接重置所有控件状态。
2. 把重复的对象（比如Inventor应用、当前文档）提取为成员变量，既能减少代码冗余，又能避免反复调用Marshal.GetActiveObject()带来的性能损耗。

内容的提问来源于stack exchange，提问作者lonnebol