将组件动态添加到Windows窗体C＃

Question

I am trying to add a list of Strings to be used as the text component of labels on a windows form. Below is the code i am using to do this. I have it generating a message box to show me what is being created, but when i add them to the form, only the first string is ever shown on the form, despite a message box popping up for each string indicating the list is populated correctly. Any help would be great.

List<Label> labelList;

    public void ShowDialog(List<String> columns)
    {
        labelList = new List<Label>();
        Form updateDialog = new Form();
        updateDialog.Width = 500;
        updateDialog.Height = 500;


        for (int i = 0; i < columns.Count(); i++ )
        {
            //Label label = new Label() {Text=columns[i].ToString() };

            labelList.Add(new Label() {Text=columns[i].ToString()});
        }

        for (int j = 0; j < labelList.Count(); j++ )
        {

            updateDialog.Controls.Add(labelList[j]);
            MessageBox.Show(labelList[j].Text.ToString());
        }

Answer 1

You need to set the location of the created labels. They are positioned on top of each other at location (0, 0).

Answer 2

Controls are being added to the form , but they are not visible to you. Just set the different location for each Label and you'll see them.

You can also precise your code by using 1 loop instead:

int yAxis = 10;
for (int i = 0; i < columns.Count(); i++ )
{
    //create label
    Label newLbl = new Label() {Text=columns[i].ToString()};
    newLbl.Location = new Point(10, yAxis * i); //will create a column of all labels, you can use your oown logic too

    //add to list
    labelList.Add(newLbl);

    //add to form
    updateDialog.Controls.Add(newLbl);

    //show on msg box
    MessageBox.Show(newLbl.Text.ToString());
}