c# - 如何委托(delegate) telerik GridView 常用方法从每个子页面的父页面调用？

Question

我正在使用 Telerik Gridview 来显示记录列表，我有超过 10 个页面，我正在使用此 gridview 并粘贴以下常见事件代码副本(有一些小的变化)在所有这些页面上:

protected void Page_Load(object sender, EventArgs e)
{
    DisplayRecords()
}

public void DisplayRecords()
{
    //Grid view names are different on different pages.
    GridView1.DataSource=Fetching records from database.
    GridView1.DataBind();
}

protected void GridView1_SortCommand(object sender, GridSortCommandEventArgs e)
{
    DisplayRecords()
}

protected void GridView1_PageIndexChanged(object sender, GridPageChangedEventArgs e)
{
    var index = e.NewPageIndex;
    DisplayRecords()
}

protected void GridView1_PageSizeChanged(object sender, GridPageSizeChangedEventArgs e)
{
    var size = e.NewPageSize;
    DisplayRecords()
}

这是我继承自以下页面的一页:

public partial class LoadSettings : ParentPage
{
    //Load events and other events
}

[Serializable]
public class ParentPage: RadAjaxPage
{

}

Page 1:**ttt.aspx**
public void DisplayRecords()
    {
        //Grid view names are different on different pages.
        GridView1.DataSource=this.GetAlltttData()
        GridView1.DataBind();
    }

    public DataTable GetAlltttData()
            {
                using (var context = new MyDataContext())
                {
                    var data = from c in context.ttt select c;
                    return MyDataContext.LINQToDataTable(data);
                }
            }


Page 2:**bbb.aspx**
public void DisplayRecords()
    {
        //Grid view names are different on different pages.
        GridView1.DataSource=this.GetAllbbbData()
        GridView1.DataBind();
    }

    public DataTable GetAllbbbData()
            {
                using (var context = new MyDataContext())
                {
                    var data = from c in context.bbb select c;
                    return MyDataContext.LINQToDataTable(data);
                }
            }

protected void rgbbb_SortCommand(object sender, GridSortCommandEventArgs e)
        {
           DisplayRecords()
        }
protected void rgbbb_PageIndexChanged(object sender, GridPageChangedEventArgs e)
        {
            var index = e.NewPageIndex;
            DisplayRecords()
        }

 protected void rgbbb_PageSizeChanged(object sender, GridPageSizeChangedEventArgs e)
        {
           var size = e.NewPageSize;
           DisplayRecords()
        }

那么我是否可以将所有这些事件放在这个 ParentPage 页面中，然后从每个子页面调用而不是用这个事件污染我的每个页面？

注意:在我的某些页面中，此DisplayRecords 方法可以包含一些参数，但其余所有事件都是通用的。

Answer 1

也许您可以将通用逻辑放入抽象类中，并使用方法(或属性)返回具体 GridView 的引用并继承自此类。然后在每个页面上你只需要实现那个方法。

像这样:

public abstract class ParentPage
{
    public virtual void DisplayRecords()
    {
        var gridView = this.GetGridView();
        gridView.DataSource = this.GetAllData();
        gridView.DataBind();
    }

    protected abstract  DataTable GetAllData();

    protected string GetSortOrder()
    {
        if (this.sortOrder != GridSortOrder.Assending)
            return string.Format("{0} DESC", this.sortExpression)
        return this.sortExpression;
    }

    protected void Page_Load(object sender, EventArgs e)
    {
        DisplayRecords();
    }

    protected void GridView1_SortCommand(object sender, GridSortCommandEventArgs e)
    {
        if (!e.Item.OwnerTableView.SortExpressions.ContainsExpression(e.SortExpression))
        {
            GridSortExpression sortExpr = new GridSortExpression();
            sortExpr.FieldName = e.SortExpression;
            sortExpr.SortOrder = GridSortOrder.Ascending;
            e.Item.OwnerTableView.SortExpressions.AddSortExpression(sortExpr);
        }
    }

    protected void GridView1_PageIndexChanged(object sender, GridPageChangedEventArgs e)
    {
        e.Item.OwnerTableView.PageIndex = e.NewPageIndex;
        DisplayRecords();
    }

    protected void GridView1_PageSizeChanged(object sender, GridPageSizeChangedEventArgs e)
    {
        e.Item.OwnerTableView.PageSize = e.NewPageSize;
        DisplayRecords();
    }
}

Page 1:**ttt.aspx**
public class **tttPage : BasePage 
{
    protected override GridView GetGridView()
    {
        //return GridView of this page 
        return GridView1;
    }

    protected override  DataTable GetAllData()
    {
        using (var context = new MyDataContext())
        {
            var data = c in context.ttt select c;
            return MyDataContext.LINQToDataTable(data);
        }
    }
}

Page 1:**bbb.aspx**
public class **bbbPage : BasePage
{
    protected override GridView GetGridView()
    {
        //return GridView of this page 
        return GridView1;
    }

    protected override  DataTable GetAllData()
    {
        using (var context = new MyDataContext())
        {
            var data = c in context.bbb select c;
            return MyDataContext.LINQToDataTable(data);
        }
    }
}

或者您可以使用虚方法将通用逻辑放入基类中，其中使用事件参数来获取 GridView，例如 e.Item.OwnerTableView。

通过将其设为虚拟，您将能够在任何页面类中覆盖此逻辑

像这样:

public abstract class ParentPage<TEntity>
{
    public virtual void DisplayRecords(GridView gridView)
    {
        gridView.DataSource = this.GetAllData();
        gridView.DataBind();
    }

    protected abstract  DataTable GetAllData();

    protected void Page_Load(object sender, EventArgs e)
    {
        DisplayRecords(e.Item.OwnerTableView);
    }

    protected void GridView_SortCommand(object sender, GridSortCommandEventArgs e)
    {
        DisplayRecords(e.Item.OwnerTableView);
    }

    protected void GridView_PageIndexChanged(object sender, GridPageChangedEventArgs e)
    {
        DisplayRecords(e.Item.OwnerTableView);
    }

    protected void GridView_PageSizeChanged(object sender, GridPageSizeChangedEventArgs e)
    {
        DisplayRecords(e.Item.OwnerTableView);
    }
}

public class **tttPage : ParentPage 
{
    protected override  DataTable GetAllData()
    {
        using (var context = new MyDataContext())
        {
            var data = c in context.ttt select c;
            return MyDataContext.LINQToDataTable(data);
        }
    }
}

public class **bbbPage : ParentPage 
{
    protected override  DataTable GetAllData()
    {
        using (var context = new MyDataContext())
        {
            var data = c in context.bbb select c;
            return MyDataContext.LINQToDataTable(data);
        }
    }
}

您也可以使用通用参数从数据库中获取值。