我怎样才能动态地清除用户控件的所有控件？ [英] How can I dynamically clear all controls in a user control?

问题描述

是否可以动态地（和一般）清除所有的用户控件的子控件的状态？ （例如，所有的文本框，DropDrownLists，单选按钮，DataGrid中，中继器等 - 有ViewState的基本上什么）

Is it possible to dynamically (and generically) clear the state of all of a user control's child controls? (e.g., all of its TextBoxes, DropDrownLists, RadioButtons, DataGrids, Repeaters, etc -- basically anything that has ViewState)

我试图避免做这样的事情：

I'm trying to avoid doing something like this:

foreach (Control c in myUserControl.Controls)
{
    if (c is TextBox)
    {
        TextBox tb = (TextBox)c;
        tb.Text = "";
    }
    else if (c is DropDownList)
    {
        DropDownList ddl = (DropDownList)c;
        ddl.SelectedIndex = -1;
    }
    else if (c is DataGrid)
    {
        DataGrid dg = (DataGrid)c;
        dg.Controls.Clear();
    }

    // etc.

}

我在寻找这样的事情：

I'm looking for something like this:

foreach (Control c in myUserControl.Controls)
    c.Clear();

......但显然是不存在的。有没有简单的方法来完成这个动态/一般？

...but obviously that doesn't exist. Is there any easy way to accomplish this dynamically/generically?

推荐答案

我要建议类似任务的，除了一个解决方案（如sixlettervariables指出的），我们需要实现为1扩展方法和essentailly接通$ P在通过控制$ pcise类型（即复制你的逻辑，你张贴在你的问题）。

I was going to suggest a solution similar to Task's except (as sixlettervariables points out) we need to implement it as 1 extension method and essentailly switch on the precise type of the control passed in (i.e. copy your logic that you posted in your question).

public static class ControlExtensions
{
    public static void Clear( this Control c )
    {
        if(c == null) {
            throw new ArgumentNullException("c");
        }
        if (c is TextBox)
        {
            TextBox tb = (TextBox)c;
            tb.Text = "";
        }
        else if (c is DropDownList)
        {
            DropDownList ddl = (DropDownList)c;
            ddl.SelectedIndex = -1;
        }
        else if (c is DataGrid)
        {
            DataGrid dg = (DataGrid)c;
            dg.Controls.Clear();
        }
        // etc....
    }
}

这是并不是特别高贵找方法，但你的code。在您的网页/控制现在是更加简洁

It is not particularly elegent looking method but your code in your page/control is now the more succinct

foreach (Control c in myUserControl.Controls) {
    c.Clear();
}

和你当然可以，现在叫 control.Clear（）在你任何地方都code。

and you can of course now call control.Clear() anywhere else in you code.

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