Question

我有这段重复的代码：

var expCodes = (from cpdet in _dataContextOrders.CodeProfileDetails
                join cpd in _dataContextOrders.CodeProfileDefinitions on cpdet.CodeProfileDefinitionID equals cpd.ID
                join cp in _dataContextOrders.CodeProfiles on cpd.CodeProfileID equals cp.ID
                join cc in _dataContextOrders.FMSCostCentres on cpdet.CostCentreID equals cc.ID
                join ec in _dataContextOrders.FMSExpenseCodes on cpdet.ExpenseCodeID equals ec.ID
                where cp.ID == Convert.ToInt32(intCostCodeProfileId)
                                  && cpdet.CostCentreID == Convert.ToInt32(intCostCentreSelected)
                                  && ec.Active == true
                select new
                {
                    ec.ID,
                    ec.CostCentreID,
                    ExpenseCodeExternalRef = ec.ExternalRef,
                    ExpenseCodeDescription = ec.Description,
                    displayExpenseCode = ec.ExternalRef + " " + ec.Description
                 }).Distinct().OrderBy(ec => ec.displayExpenseCode);

ddlExpCode1.DataSource = expCodes;
ddlExpCode1.DataTextField = "displayExpenseCode";
ddlExpCode1.DataValueField = "ID";

我想做的是将它自己放入一个类，就像我们在LinqToSql之前做的那样，我可以从我的aspx.cs页面调用，使用2个参数，intCostCodeProfileId和intCostCodeProfileId，它将返回下拉列表的数据。

我该怎么做？

Answer 1

您必须创建一个与select语句（ID，CostCentreId等）中的属性匹配的模型类。然后将select new {修改为select new FreshlyCreatedModelClass() {。

从您的方法返回匿名类型的唯一方法是使用IEnumerable<object>或IEnumerable<dynamic>，这两者都不应该在这种情况下推荐。您的方法应返回IEnumerable<FreshlyCreatedModelClass>（如果您需要进一步构建查询，则可以使用IQueryable<FreshlyCreatedModelClass>。）

对模型类进行排序后，只需将代码移动到单独的方法即可。

Answer 2

创建一个普通类（例如Connection.cs）并添加如下代码：

public class MyDataSourceReturner
{
    public static Object retDatasource(Object _dataContextOrders, int intCostCodeProfileId){
    var expCodes = (from cpdet in _dataContextOrders.CodeProfileDetails
            join cpd in _dataContextOrders.CodeProfileDefinitions on cpdet.CodeProfileDefinitionID equals cpd.ID
            join cp in _dataContextOrders.CodeProfiles on cpd.CodeProfileID equals cp.ID
            join cc in _dataContextOrders.FMSCostCentres on cpdet.CostCentreID equals cc.ID
            join ec in _dataContextOrders.FMSExpenseCodes on cpdet.ExpenseCodeID equals ec.ID
            where cp.ID == Convert.ToInt32(intCostCodeProfileId)
                              && cpdet.CostCentreID == Convert.ToInt32(intCostCentreSelected)
                              && ec.Active == true
            select new
            {
                ec.ID,
                ec.CostCentreID,
                ExpenseCodeExternalRef = ec.ExternalRef,
                ExpenseCodeDescription = ec.Description,
                displayExpenseCode = ec.ExternalRef + " " + ec.Description
             }).Distinct().OrderBy(ec => ec.displayExpenseCode);

    return expCodes;
    }
}

之后您可以像这样使用此代码：

ddlExpCode1.DataSource = MyDataSourceReturner.retDatasource(_dataContextOrders, 5);

并收到您的DataSource。

我可以将它放在单独的课程中吗？

2 个答案: