在C＃Windows窗体中为动态创建的组合框调用SelectedIndexChanged事件

Question

我已经在C＃中创建了一个Windows窗体。 我正在生成2个动态组合框，即MajorComboHead和SubComboHead。 我所做的是在创建控件时加载了MajorComboHead。 最终，我在MajorComboHead SelectedIndexChanged事件（在动态控件创建时动态创建的事件处理程序）上加载了SubComboHead。

SelectedIndexChanged事件可以正常工作，并且两个下拉列表都可以正常加载，但是问题是SubComboHead在MajorComboHead更改事件上而不是在加载项目。 在窗体加载时或在创建动态控件时，无法调用MajorComboHead_SelectedIndexChanged事件。

请帮助我。 以下是MajorComboHead_SelectedIndexChanged事件和动态控件创建函数的代码：-

public void dynamicControls()
 {
.......................All about declaring and creating dynamic controls..................


        con2.Open();
        SqlDataAdapter adp1 = new SqlDataAdapter("select distinct * from MajorHead where(projectCode='" + projectId + "' AND (headName!='" + "Cash" + "' AND headName!='"+"Bank"+"'))", con2);
        DataSet ds1 = new DataSet();
        adp1.Fill(ds1, "MajorHead");
        MajorCombohead.DataSource = ds1.Tables["MajorHead"];
        MajorCombohead.DisplayMember = "headName";
        MajorCombohead.ValueMember = "headCode";
        con2.Close();

        MajorCombohead.SelectedIndexChanged += new EventHandler(MajorCombohead_SelectedIndexChanged);
}


public void MajorCombohead_SelectedIndexChanged(object sender, EventArgs e)
    {            
        ComboBox clicksave = sender as ComboBox;
        string savename = clicksave.Name;



        foreach (Control f1 in panel1.Controls)
        {
            if (f1.GetType() == typeof(ComboBox) && f1.Name == ("Maj" + savename))
            {                                      

                //.....................loading sub head........................
                foreach (Control f2 in panel1.Controls)
                {
                    if (f2.GetType() == typeof(ComboBox) && f2.Name == ("Sub" + savename))
                    {
                        con1.Open();
                        SqlDataAdapter adp2 = new SqlDataAdapter("select distinct * from SubHead where(majorHeadName='" + f1.Text + "' AND projectCode='" + projectId + "')", con1);
                        DataSet ds2 = new DataSet();
                        adp2.Fill(ds2, "SubHead");
                        int countMeNow = ds2.Tables[0].Rows.Count;
                        ((ComboBox)f2).DataSource = ds2.Tables["SubHead"];
                        ((ComboBox)f2).DisplayMember = "headName";
                        ((ComboBox)f2).ValueMember = "headCode";                           
                        con1.Close();
                    }
                }
                //.....................loading sub head........................


            }
        }


    }

Answer 1

地点

MajorCombohead.SelectedIndexChanged += new EventHandler(MajorCombohead_SelectedIndexChanged);

在加载MajorCombohead之前（声明变量，添加事件侦听器，然后将其放在表单上）。