Question

我想创建一个接受任意数量参数的类和函数（它也可以是一个数组）。

我想要实现的是，我想传递存储过程所需的所有参数及其数据类型，它应该将它们作为SqlParameter数组返回

DAL CODE

public DataSet createProblemStatement()
        {
            DataSet createProblemStatement = SqlHelper.ExecuteDataset(CCSVas.Constants.ConnectionString.DBConnection, "usp_ProblemStatements_Add", ProblemStatement.createProblemStatement("d", "d", "d", "d", "d"));
             return createProblemStatement;

        }

将分配值的功能

public static SqlParameter[] createProblemStatement(string strProblemTitle, string strProblemOwner, string strBusinessPurpose, string strProblemDescription, string strAssociateId) {
            SqlParameter ProblemTitle = new SqlParameter();
            ProblemTitle.DbType = DbType.String;
            ProblemTitle.Value = strProblemTitle;
            ProblemTitle.ParameterName = "@strProblemTitle";
             SqlParameter ProblemOwner = new SqlParameter();
            ProblemOwner.DbType = DbType.String;
            ProblemOwner.Value = strProblemOwner;
            ProblemOwner.ParameterName = "@strProblemOwner";
            SqlParameter BusinessPurpose = new SqlParameter();
            BusinessPurpose.DbType = DbType.String;
            BusinessPurpose.Value = strBusinessPurpose;
            BusinessPurpose.ParameterName = "@strBusinessPurpose";
             SqlParameter ProblemDescription = new SqlParameter();
            ProblemDescription.DbType = DbType.String;
            ProblemDescription.Value = strBusinessPurpose;
            ProblemDescription.ParameterName = "@strProblemDescription";
             SqlParameter AssociateId = new SqlParameter();
            AssociateId.DbType = DbType.String;
            AssociateId.Value = strBusinessPurpose;
            AssociateId.ParameterName = "@strAssociateId";

            SqlParameter[] createProblemStatement = { ProblemTitle, ProblemOwner, BusinessPurpose, ProblemDescription, AssociateId };

            return createProblemStatement;

        }

我对此功能的问题是，这只接受已定义的参数且不可重复使用

Answer 1

使用 params 关键字。通过使用params关键字，您可以指定一个带有可变数量参数的方法参数。

params (C# Reference)

Answer 2

如果您使用的是Dot net Framework 4.0+，请使用dynamic其他方式使用object。

以下是代码段。

public static SqlParameter[] createProblemStatement(params dynamic[] test)
{
    var lstParam = new List<SqlParameter>();

    foreach (var item in test)
    {
        var paramType = item.GetType();
        if (paramType == typeof(string))
        {
            //Do something.
            lstParam.Add(obj);
        }
        else if (paramType == typeof(int))
        {
            //Do something.
            lstParam.Add(obj);
        }

    }
    return lstParam.ToArray();
}

Answer 3

使用params关键字获取＆＃34;不确定长度＆＃34;功能然后只是通过SqlParameters

public DataSet CreateProblemStatement(params SqlParamter[] paremeters)
{
    DataSet createProblemStatement = SqlHelper.ExecuteDataset(CCSVas.Constants.ConnectionString.DBConnection, "usp_ProblemStatements_Add", paremeters);
     return createProblemStatement;

}

你会这样称呼：

var problemTitle = new SqlParameter("@strProblemTitle", "Some Title");
var problemOwner = new SqlParameter("@strProblemOwner", "Owner Name");
...
var result = CreateProblemStatement(problemTitle, problemOwner, businessPurpose, problemDescription, associateId);

Answer 4

您可以创建一个帮助程序类，使您可以以受控方式构造Parameter数组，而不会遇到每种情况的方法实现。

首先为List

的Extension方法创建一个类

// helper for Adding parameters to a list
public static class SqlParameters
{  
    // or have strongly typed overloads
    public static List<SqlParameter> Add(
        this List<SqlParameter> list, 
        string paramName, 
        object value)
    {  
        var p =new SqlParameter(
                    paramName, 
                    Map(value.GetType()));
        p.Value = value;
        list.Add(p);
        return list;
    }

    private static DbType Map(Type type)
    {
        DbType dbtype = DbType.Object;
        if (type == typeof(System.String))
        {
            dbtype = DbType.String;
        }
        if (type == typeof(System.Int32))
        {
            dbtype = DbType.Int32;
        }
        return dbtype;
    }
}

然后在Builder中使用它作为参数：

// builder
public class ProblemStatement
{
    List<SqlParameter> list = new List<SqlParameter>();

    // single parameter
    public ProblemStatement Title(string value)
    {
       list.Add("strProblemTitle", value);
       return this;
    }
    public ProblemStatement Owner(string value)
    {
       list.Add("strProblemOwner", value);
       return this;
    }
    public ProblemStatement Description(string value)
    {
       list.Add("strProblemOwner", value);
       return this;
    }
    // a couple of parameters together at once...
    public ProblemStatement AddProblem(string title, 
                                       string owner, 
                                       string description)
    {
       return Title(title)
              .Owner(owner)
              .Description(description); // re-use methods
    }

    public SqlParameter[] ToArray()
    {
        return list.ToArray();
    }
}

构建器的用法：

DataSet createProblemStatement = SqlHelper.ExecuteDataset(
       CCSVas.Constants.ConnectionString.DBConnection, 
       "usp_ProblemStatements_Add", 
       new ProblemStatement().Title("d")
                             .Owner("d")
                             .Description("d")
                             .ToArray());
 return createProblemStatement;

请注意，您可以在构建器中定义任意数量的参数，而无需指定和/或使用它们。

如何创建一个接受n个参数并相应返回对象的函数

4 个答案: