Count the number of TextBoxes and CheckBoxes in a

问题:

My requirement is to count the total number of TextBox and CheckBox present directly inside the form with the id="form1", when the user clicks on the Button 'btnGetCount'. Here is the code which I have tried but it doesn't count anything and counter remains at zero, though I have three TextBoxes and two CheckBoxes in the form. However, if I remove foreach loop and pass TextBox control = new TextBox(); instead of the present code then it counts the first TextBox and countTB returns the value as one.

protected void btnGetCount_Click(object sender, EventArgs e)
    {
        Control control = new Control();

        int countCB = 0;
        int countTB = 0;
        foreach (Control c in this.Controls)
        {
            if (control.GetType() == typeof(CheckBox))
            {
                countCB++;
            }
            else if (control is TextBox)
            {
                countTB++;
            }
        }

        Response.Write("No of TextBoxes: " + countTB);
        Response.Write("<br>");
        Response.Write("No of CheckBoxes: " + countCB);
    }

回答1:

You must recursively loop through other controls.

    <form id="form1" runat="server">
    <div>
    <asp:TextBox ID="txt" runat="server"></asp:TextBox>
    <asp:CheckBox ID="cb" runat="server"></asp:CheckBox>
    </div>
    </form>

protected void Page_Load(object sender, EventArgs e)
{
    var controls = form1.Controls;
    var tbCount = 0;
    var cbCount = 0;
    CountControls(ref tbCount, controls, ref cbCount);

    Response.Write(tbCount);
    Response.Write(cbCount);
}

private static void CountControls(ref int tbCount, ControlCollection controls, ref int cbCount)
{
    foreach (Control wc in controls)
    {
        if (wc is TextBox)
            tbCount++;
        else if (wc is CheckBox)
            cbCount++;
        else if(wc.Controls.Count > 0)
            CountControls(ref tbCount, wc.Controls, ref cbCount);
    }
}

回答2:

It allows gives you zero since you are counting the type of your Control control which is not available change your code to :

protected void btnGetCount_Click(object sender, EventArgs e)
    {

        int countCB = 0;
        int countTB = 0;
        foreach (Control c in this.Controls)
        {
            if (c.GetType() == typeof(CheckBox))
            {
                countCB++;
            }
            else if (c.GetType()== typeof(TextBox))
            {
                countTB++;
            }
        }

        Response.Write("No of TextBoxes: " + countTB);
        Response.Write("<br>");
        Response.Write("No of CheckBoxes: " + countCB);
    } 

回答3:

I believe you have to be recursive, this.Controls will only return the controls that are its immediate children. If the TextBox is within a control group within there, you will need to see the containers controls as well.

See the answer to this other stackoverflow: How to get ALL child controls of a Windows Forms form of a specific type (Button/Textbox)?

EDIT: I realize the answer is for WinForms, but the solution still applies.

回答4:

Just by doing some minor change in the code suggested by Alyafey, pcnThird and Valamas I wrote this code which works.

protected void btnGetCount_Click(object sender, EventArgs e)
    {

        int countCB = 0;
        int countTB = 0;
        foreach (Control c in form1.Controls) //here is the minor change
        {
            if (c.GetType() == typeof(CheckBox))
            {
                countCB++;
            }
            else if (c.GetType()== typeof(TextBox))
            {
                countTB++;
            }
        }

        Response.Write("No of TextBoxes: " + countTB);
        Response.Write("<br>");
        Response.Write("No of CheckBoxes: " + countCB);
    }