在GridView控件添加控件动态 [英] Adding controls in gridview dynamically

问题描述

我需要控件添加到动态的GridView，所以我加了一个占位符，但它给我一个错误。

 保护无效GridView1_RowDataBound（对象发件人，GridViewRowEventArgs E）
{
    占位符plachldr = e.Row.FindControl（PLACEHOLDER2）作为占位符;
    按钮BTN =新按钮（）{ID =btnShhow，文本=显示};
    plachldr.Controls.Add（BTN）;    占位符占位符= e.Row.FindControl（PLACEHOLDER1）作为占位符;
    文本框TXT1 =新的TextBox（）;
    placeholder.Controls.Add（TXT1）;
}
 

同时加入了控制占位符，则是给我下面的错误：

  

对象引用未设置到对象的实例。

下面是我的GridView的标记：

 ＆LT; ASP：GridView控件ID =GridView1=服务器的AutoGenerateColumns =FALSEOnSelectedIndexChanging =GridView1_SelectedIndexChangingonrowdatabound =GridView1_RowDataBound＆GT;
    ＆LT;柱体和GT;
        ＆LT; ASP：BoundField的数据字段=名称的HeaderText =名称/＆GT;
        ＆LT; ASP：BoundField的数据字段=薪资的HeaderText =工资/＆GT;
        ＆LT; ASP：的TemplateField＆GT;
            ＆LT;＆ItemTemplate中GT;
                ＆LT; ASP：占位符ID =PLACEHOLDER1=服务器＆GT;＆LT; / ASP：占位符＆GT;
            ＆LT; / ItemTemplate中＆GT;
        ＆LT; / ASP：的TemplateField＆GT;
        ＆LT; ASP：的TemplateField＆GT;
            ＆LT;＆ItemTemplate中GT;
                ＆LT; ASP：占位符ID =PLACEHOLDER2=服务器＆GT;＆LT; / ASP：占位符＆GT;
            ＆LT; / ItemTemplate中＆GT;
        ＆LT; / ASP：的TemplateField＆GT;
    ＆LT; /专栏＆GT;
＆LT; / ASP：GridView的＆GT;
 

解决方案

您需要检查plachldr或占位符为空或不是，也检查 ROWTYPE

 保护无效GridView1_RowDataBound（对象发件人，GridViewRowEventArgs E）
{  如果（如果（e.Row.RowType == DataControlRowType.DataRow）
  {
    占位符plachldr = e.Row.FindControl（PLACEHOLDER2）作为占位符;
    如果（plachldr！= NULL）
    {
     按钮BTN =新按钮（）{ID =btnShhow，文本=显示};
     plachldr.Controls.Add（BTN）;
    }    占位符占位符= e.Row.FindControl（PLACEHOLDER1）作为占位符;
    如果（占位符！= NULL）
    {
     文本框TXT1 =新的TextBox（）;
     placeholder.Controls.Add（TXT1）;
    }
   }}
 

I need to add controls to a GridView dynamically, so I added a PlaceHolder, but it it giving me an error.

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    PlaceHolder plachldr = e.Row.FindControl("PlaceHolder2") as PlaceHolder;
    Button btn = new Button() { ID = "btnShhow", Text = "Show" };
    plachldr.Controls.Add(btn);

    PlaceHolder placeholder = e.Row.FindControl("PlaceHolder1") as PlaceHolder;
    TextBox txt1 = new TextBox();
    placeholder.Controls.Add(txt1);
}

While adding the control to the PlaceHolder, is is giving me the following error:

Object reference not set to an instance of an object.

Here's the markup for my GridView:

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnSelectedIndexChanging="GridView1_SelectedIndexChanging" onrowdatabound="GridView1_RowDataBound">    
    <Columns>  
        <asp:BoundField DataField="Name" HeaderText="Name" />  
        <asp:BoundField DataField="Salary" HeaderText="Salary" />      
        <asp:TemplateField>
            <ItemTemplate>  
                <asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
            </ItemTemplate> 
        </asp:TemplateField>      
        <asp:TemplateField>  
            <ItemTemplate>  
                <asp:PlaceHolder ID="PlaceHolder2" runat="server"></asp:PlaceHolder>     
            </ItemTemplate>  
        </asp:TemplateField>      
    </Columns>
</asp:GridView>

解决方案

You need to check plachldr or placeholder is null or not and also check for the RowType

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{

  if( if (e.Row.RowType == DataControlRowType.DataRow) 
  {
    PlaceHolder plachldr = e.Row.FindControl("PlaceHolder2") as PlaceHolder;
    if(plachldr!=null)
    {
     Button btn = new Button() { ID = "btnShhow", Text = "Show" };
     plachldr.Controls.Add(btn);
    }

    PlaceHolder placeholder = e.Row.FindControl("PlaceHolder1") as PlaceHolder;
    if(placeholder!=null)
    {
     TextBox txt1 = new TextBox();
     placeholder.Controls.Add(txt1);
    }
   }

}

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