控件在winforms中不被继承

Question

我有一个返回类型数据表的函数

public DataTable GetAllPrimaryKeyTables(string ConnectionString)
{ 
    // Create the datatable 
    DataTable dtListOfPrimaryKeyTables = new DataTable("tableNames");

    // Query to select primary key tables.
    string selectPrimaryKeyTables = @"SELECT 
                                           TABLE_NAME
                                          AS
                                           TABLES
                                        FROM 
                                           INFORMATION_SCHEMA.TABLE_CONSTRAINTS
                                       WHERE 
                                           CONSTRAINT_TYPE = 'PRIMARY KEY'
                                         AND
                                           TABLE_NAME <> 'dtProperties'
                                    ORDER BY
                                           TABLE_NAME";

    // put your SqlConnection and SqlCommand into using blocks! 
    using(SqlConnection sConnection = new SqlConnection(ConnectionString))
    using(SqlCommand sCommand = new SqlCommand(selectPrimaryKeyTables, sConnection))
    {
        try
        {
            // Create the dataadapter object 
            SqlDataAdapter sDataAdapter = new SqlDataAdapter(selectPrimaryKeyTables, sConnection);


            // Fill the datatable - no need to open the connection, the SqlDataAdapter will do that all by itself  
            // (and also close it again after it is done) 
            sDataAdapter.Fill(dtListOfPrimaryKeyTables);
            //using(StringWriter sw = new StringWriter())
            //{
            //    dtListOfPrimaryKeyTables.WriteXml(sw);
            //    sw.WriteLine();
            //    result = sw.ToString();
            //}
        }
        catch(Exception ex)
        {
            //All the exceptions are handled and written in the EventLog. 
            EventLog log = new EventLog("Application");
            log.Source = "MFDBAnalyser";
            log.WriteEntry(ex.Message);
        }
    }

    // return the data table to the caller 
    return dtListOfPrimaryKeyTables;
}

我这样称呼它......

public class PrimaryKeyChecker : IMFDBAnalyserPlugin
{
    public DataTable RunAnalysis(string ConnectionString)
    {
        return GetAllPrimaryKeyTables(ConnectionString);
    }

在 IMFDBAnalyserPlugin 我有

namespace MFDBAnalyser
{
    public interface IMFDBAnalyserPlugin
    {
        DataTable RunAnalysis(string ConnectionString);
    }

在我的主要项目背景上

private void btnStartAnalysis_Click(object sender, EventArgs e)
{
    SqlConnectionStringBuilder objConnectionString = new SqlConnectionStringBuilder();
    objConnectionString.DataSource = txtHost.Text;
    objConnectionString.UserID = txtUsername.Text;
    objConnectionString.Password = txtPassword.Text;
    string[] arrArgs = {objConnectionString.ConnectionString};

    string assemblyName = "PrimaryKeyChecker.dll";
    Assembly assembly = Assembly.LoadFrom(assemblyName);
    Type local_type = assembly.GetType("PrimaryKeyChecker.PrimaryKeyChecker");
    MethodInfo objMI = local_type.GetMethod("RunAnalysis");
    ConstructorInfo ci = local_type.GetConstructor(Type.EmptyTypes);
    object responder = ci.Invoke(null);
    object response = objMI.Invoke(responder, arrArgs);

但是当我调试时，响应对象只返回空数据表，因为我无法在第一个函数中提供数据源，因为它没有继承那里的控件...

希望问题对你们来说是部分清楚的。它应该在调试时给出所有表的列表，但它没有将数据网格 dgResultView 带到那里给它一个数据源...

Answer 1

这与继承无关；看起来您正在捕获并记录异常：

    catch(Exception ex)
    {
        //All the exceptions are handled and written in the EventLog. 
        EventLog log = new EventLog("Application");
        log.Source = "MFDBAnalyser";
        log.WriteEntry(ex.Message);
    }

我会先看看那里；很可能有东西在扔，并告诉你为什么......如果我不得不猜测，看起来你可能失踪了：

sConnection.Open();

返回 anything 的事实告诉我这只是一个例外。

个人我只会让一个未预料到的异常冒泡到 UI，然后让 UI 通过记录它并显示适当的#fail 页面来做出反应。

此外，如果可能，将插件强制转换为接口：

string assemblyName = "PrimaryKeyChecker.dll";
Assembly assembly = Assembly.LoadFrom(assemblyName);
Type local_type = assembly.GetType("PrimaryKeyChecker.PrimaryKeyChecker");
IMFDBAnalyserPlugin analyser =
   (IMFDBAnalyserPlugin)Activator.CreateInstance(local_type);
DataTable response = analyser.RunAnalysis(objConnectionString.ConnectionString);