Question

我在内容页面中使用了Find控件来查找内容页面本身的文本框。但是它返回null。我已经尝试了很多方法，但即使下面没有工作也是我的代码......

private void showw()
    {
        try
        {
            Page page = HttpContext.Current.Handler as Page;
            ContentPlaceHolder mainContent = (ContentPlaceHolder)page.FindControl("ContentPlaceHolder1");
            // ContentPlaceHolder mainContent = (ContentPlaceHolder)page.Page.Master.FindControl(");

            TextBox TxtPId = (TextBox)mainContent.FindControl("ContentPlaceHolder1_TxtPId");
            TextBox TxtPId1 = (TextBox)this.Master.FindControl("Content2").FindControl("TxtPLName ");
            if (TxtPId!=null)
            {
                insertString = @"select [Patientid] as 'Patient id' ,[LastName]  as'Last Name',[FirstName],[MiddleName],[AliasName] , [PHN],[PhoneNo], CONVERT(varchar,DateOfBirth,105) as 'Date Of Birth' from PatientMaster where Patientid like   '" + TxtPId+ "%'";
                TxtPId1.Text = "Last name";
            }
            GridView GridView1 = (GridView)page.FindControl("ContentPlaceHolder1_GridView1");
            GridView1.DataSource = null;
            SqlCommand cmd = new SqlCommand(insertString, connect);
            SqlDataAdapter adapter = new SqlDataAdapter(cmd);
            DataSet ds = new DataSet();
            adapter.Fill(ds, "PatientMaster");
            GridView1.DataSource = ds;
            if (ds.Tables[0].Rows.Count == 0)
                Label1.Visible = true;
            else
                Label1.Visible = false;
            GridView1.DataBind();
            ModalPopupExtender1.Show();
        }
        catch {    }
    }

注意：
我必须在内容页面中为该页面文本框使用查找控件，而不是母版页。

Answer 1

1。在我们使用FindControl获取对MainContent的引用之前，我们首先需要对母版页控件的引用。获得对母版页的引用后，我们可以通过MainContent ContentPlaceHolder引用FindControl，并从那里引用TextBox（再次使用FindControl ）。

代码：

public partial class WebForm1 : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        //can be called on page load
        show();
    }

    protected void btnShow_Click(object sender, EventArgs e)
    {
        //can be called on any event
        show();
    }

    private void show()
    {
        MasterPage ctl00 = FindControl("ctl00") as MasterPage;

        // Get a reference to the ContentPlaceHolder
        ContentPlaceHolder MainContent = ctl00.FindControl("ContentPlaceHolder1") as ContentPlaceHolder;

        // Reference the Label and TextBox controls
        TextBox myControl1 = MainContent.FindControl("txtTest") as TextBox; //your textbox Id here *ex:* txtPId

        if (myControl1 != null)
        {
            //Control myControl2 = myControl1.Parent;
            //Response.Write("Parent of the text box is : " + myControl2.ID);
            Response.Write("Text is:  " + myControl1.Text);
        }
        else
        {
            Response.Write("Control not found");
        }
    }
}

需要提及

2。 ctl00，因为母版页及其ContentPlaceHolders都充当命名容器。

enter image description here

它有效！
有用的文章：Control ID Naming Issues

在内容页面中查找返回null的控件

1 个答案:

代码：