Question

我正在为我的同事用SQL Server（Express）编写一种民主的程序。

因此我相处得很好，但是我失败了大约一个小时没有，创建一个使用带参数的SqlCommand的简单方法，可以为null，但不要总是。

我目前的解决方案＆＃34;看起来像这样：

public bool CreateSubTopic(string subtopic, DateTime enddate, int maxParts, int BitKeepEntries)
{
    Connected = true;
    var myDict = GetSubtopics(HelpClass.TopicId);
    if (myDict.ContainsKey(subtopic))
    {
        return false;
    }

    myCommand = null;
    myCommand = new SqlCommand("insert into SubtopicsParameters(FK_Topic, Subtopic, StartDate, Enddate, MaxParticipants, KeepsEntries) values(" +
                                HelpClass.TopicId + "," +
                                subtopic + "," +
                                DateTime.Today + "," +
                                enddate + "," +
                                maxParts + "," +
                                BitKeepEntries + ")");
    myCommand.ExecuteNonQuery();
    Connected = false;
    return true;
}

我写的表有额外的主键PK_ID。根据表单上的复选框，FK_Topic，Enddate和MaxParticipants列可以为空。

问题是，我可以写出7种不同的方法，但它会很脏。

你有解决方案吗？

€：我现在使用的解决方案如下：

public bool CreateSubTopic(string subtopic, DateTime enddate, int maxParts, bool KeepEntries)
{
    var myDict = GetSubtopics(HelpClass.TopicId);
    if (myDict.ContainsKey(subtopic))
    {
        return false;
    }
    Connected = true;
    myCommand = null;
    myCommand = new SqlCommand("insert into SubtopicsParameters(FK_Topic, Subtopic, StartDate, Enddate, MaxParticipants, KeepsEntries) values(" +
        "@FKParam," + " @SubtopicParam," + "@Startdateparam," + "@Enddateparam," + "@MaxPartsParam," + "@KeepEntriesParam)", myConnection);


    myCommand.Parameters.AddWithValue("FkParam", HelpClass.TopicId);
    myCommand.Parameters.AddWithValue("SubtopicParam", subtopic);
    myCommand.Parameters.AddWithValue("@Startdateparam", DateTime.Today);
    if (enddate != DateTime.Today)
    {
        myCommand.Parameters.AddWithValue("@Enddateparam", enddate);
    }
    else
    {
        myCommand.Parameters.AddWithValue("@Enddateparam", DBNull.Value);
    }
    if (maxParts == 0)
    {
        myCommand.Parameters.AddWithValue("@MaxPartsParam", DBNull.Value);
    }
    else
    {
        myCommand.Parameters.AddWithValue("@MaxPartsParam", maxParts);
    }
    if(KeepEntries == true)
    {  
        myCommand.Parameters.AddWithValue("@KeepEntriesParam",  1);
    }
    else
    {
        myCommand.Parameters.AddWithValue("@KeepEntriesParam", 0);
    }
    myCommand.ExecuteNonQuery();
    Connected = false;
    return true;
}

这是有效的，是安全的，并根据您的意见和答案:)谢谢。

Answer 1

动态地将参数添加到SQLCommand.Parameters集合。

以下是SqlCommand.Parameters

的示例

Answer 2

试试这个

public bool CreateSubTopic(string subtopic, DateTime enddate, int maxParts, int BitKeepEntries)
{
   Connected = true;
   var myDict = GetSubtopics(HelpClass.TopicId);
   if (myDict.ContainsKey(subtopic))
   {
    return false;
   }

    myCommand = null;
    myCommand = new SqlCommand("insert into SubtopicsParameters(FK_Topic, Subtopic, StartDate, Enddate, MaxParticipants, KeepsEntries) values(@topic,@stopic,@sd,@ed,@partici,@KEntries);
    if(HelpClass.TopicId=="")
        myCommand.Parameters.AddWithValue("@topic",System.DBNull.Value);
    else 
        myCommand.Parameters.AddWithValue("@topic",HelpClass.TopicId);

    if(subtopic=="")
        myCommand.Parameters.AddWithValue("@stopic",System.DBNull.Value);
    else 
        myCommand.Parameters.AddWithValue("@stopic",subtopic);

    myCommand.Parameters.AddWithValue("@sd",DateTime.Today);

    if(enddate=="")
        myCommand.Parameters.AddWithValue("@ed",System.DBNull.Value);
    else 
        myCommand.Parameters.AddWithValue("@ed",enddate);

    if(maxParts=="")
        myCommand.Parameters.AddWithValue("@partici",System.DBNull.Value);
    else 
        myCommand.Parameters.AddWithValue("@partici",maxParts); 

    if(BitKeepEntries=="")
        myCommand.Parameters.AddWithValue("@KEntries",System.DBNull.Value);
    else 
        myCommand.Parameters.AddWithValue("@KEntries",BitKeepEntries);      

    myCommand.ExecuteNonQuery();
    Connected = false;
    return true;
}

如何轻松地取消SqlCommand的某些部分？

2 个答案: