如何清除面板中的TextBox控件

如何解决如何清除面板中的TextBox控件

| 我想清空面板中的文本框控件。 请解释。 下面是我的代码：

<asp:Panel ID=\"Panel_CreateLead\" runat=\"server\" Visible=\"false\" BackColor=\"#eff2f6\"  Width=\"98%\">

<asp:Literal ID=\"LiteralNoLead\" runat=\"server\" Text=\"<span style=\'color:red\'>No Lead Exists. Please fill the Lead Template to Create New Lead.</span>\"></asp:Literal> 
<asp:Table ID=\"Table_CreateLead\" runat=\"server\" Width=\"98%\"  CellSpacing=\"1\"  CellPadding=\"1\"  
        Font-Names=\"Tahoma\" BorderColor=\"#eff2f6\" BorderStyle=\"Dashed\">
<asp:TableHeaderRow HorizontalAlign=\"Center\">
    <asp:TableHeaderCell Text=\"Lead Template\" Font-Bold=\"true\" ColumnSpan=\"4\"  Font-Size=\"Large\" />
</asp:TableHeaderRow>
<asp:TableRow ID=\"TableRow11\" runat=\"server\">
       <asp:TableCell Text=\"General\"  Font-Bold=\"true\"  ForeColor=\"Blue\"></asp:TableCell>
</asp:TableRow>
<asp:TableRow ID=\"TableRow1\"  runat=\"server\">
    <asp:TableCell Text=\"Topic\">
        <asp:Literal ID=\"Literal_Topic\"  Text=\"<span style=\'color:red\'>*</span>\" runat=\"server\" />
    </asp:TableCell>
    <asp:TableCell ColumnSpan=\"3\">
        <asp:TextBox ID=\"TextBox_leadname\" Width=\"80%\" runat=\"server\"></asp:TextBox> 
        <asp:RequiredFieldValidator ID=\"RequiredFieldValidator_TextBox_leadname\" runat=\"server\"  ControlToValidate=\"TextBox_leadname\" ValidationGroup=\"LeadVaidation\" ErrorMessage=\"Enter Topic\" />
    </asp:TableCell>
</asp:TableRow> 
<asp:TableRow ID=\"TableRow23\" runat=\"server\">
   <asp:TableCell Text=\"Currency\" ></asp:TableCell>
    <asp:TableCell>
        <asp:DropDownList ID=\"DropDownList_Currency\" runat=\"server\">
        </asp:DropDownList>
    </asp:TableCell>
        <asp:TableCell Text=\"No. of Employees\" ></asp:TableCell>
    <asp:TableCell>
        <asp:TextBox ID=\"TextBox_Employees\" runat=\"server\"></asp:TextBox> 
    </asp:TableCell>
 </asp:TableRow>
 <asp:TableRow>
    <asp:TableCell>
        <asp:Button ID=\"Button_lead\" runat=\"server\" Text=\"Submit\" OnClick=\"create_lead\" ValidationGroup=\"LeadVaidation\"/>
    </asp:TableCell>
     <asp:TableCell>
     <asp:Literal ID=\"Literal_lead\" runat=\"server\"></asp:Literal>
 </asp:TableCell>
</asp:TableRow>
</asp:Table>
</asp:Panel>

我已经使用了方法clearText（Panel_CreateLead）;页面加载不起作用。 cleartext（）中使用的代码：

private void clearText(Panel PanelID)
{
     foreach (Control c in PanelID.Controls)
     {
         if (c is TextBox)
         {
             TextBox questionTextBox = c as TextBox; 
             if (questionTextBox != null)
             {
                 questionTextBox.Text = \"\";
             }
         }
     }
}

所有这些都不起作用。请帮忙。     

解决方法

        您需要一种递归方法来获取所有控件，否则您将仅在面板下立即获取控件。要使用递归方法获取所有控件，可以使用以下命令：

public static IEnumerable<TextBox> GetAllControls(this Control parent)
{
    foreach (Control control in parent.Controls)
    {
        yield return control;
        foreach(Control descendant in control.GetAllControls())
        {
            yield return descendant;
        }
    }
}

您可以修改以仅查找文本框，也可以将此方法用作

Panel.GetAllControls.OfType<TextBox>()

并使用面板中的所有文本框。     ,        用于按类型递归获取所有控件的扩展方法：

public static IEnumerable<Control> GetChildControls(this Control control) where TControl : Control
{
    var children = (control.Controls != null) ? control.Controls.OfType<Control>() : Enumerable.Empty<Control>();
    return children.SelectMany(c => GetChildControls(c)).Concat(children);
}

用法：

IEnumerable<TextBox> textBoxes = panel.Controls.GetChildControls().OfType<TextBox>();
foreach (TextBox tb in textBoxes)
{
    tb.Text = \"\";
}

    ,        这只会清除直接属于您的孩子的文本框。在您的代码中，如果您执行了类似流程这样的工作，它将起作用

private void clearText(control PanelID)
{
    foreach (Control c in PanelID.Controls)
    {
        if (c is TextBox)
        {
            TextBox questionTextBox = c as TextBox; 
            if (questionTextBox != null)
            {
                questionTextBox.Text = \"\";
            }
        }

        if(c.Controls.count > 0)
        {
            cleartest(c)
        }
    }
}

    ,        如何清空表格中的所有文本框，然后依次是

tr

，

td

...

foreach (Control c in Table3.Controls)
{
    if (c is System.Web.UI.HtmlControls.HtmlTableRow)
    {
        System.Web.UI.HtmlControls.HtmlTableRow tr;
        tr = (System.Web.UI.HtmlControls.HtmlTableRow)c;
        foreach (Control td in tr.Controls)
        {
            if (td is System.Web.UI.HtmlControls.HtmlTableCell)                        
            {
                System.Web.UI.HtmlControls.HtmlTableCell td1;
                td1 = (System.Web.UI.HtmlControls.HtmlTableCell)td;
                    foreach (Control txtBox in td1.Controls)
                    {
                        if(txtBox is TextBox)
                        {
                            TextBox tt = txtBox as TextBox;
                            tt.Text = string.Empty;
                        }
                    }
                }
            }
        }
    }
}