在dymanic control -combobox中获取所选项目 [英] To get selected item in dymanic control -combobox

问题描述

我动态创建了comboBox。但我需要从SelectedIndexChanged中选择值。但是因为对象引用没有设置为对象的实例而得到错误。

I have created comboBox dynamically. But i need to select the value from " SelectedIndexChanged". But iam getting error as "Object reference not set to an instance of an object."

 private ComboBox TimeIntervel;
int Stimer; 
public void set control()
{
   ComboBox TimeIntervelCmb = new ComboBox();

 TimeIntervelCmb.Location = new Point(50,70);
            TimeIntervelCmb.Name = "ComboBoxTime";
            TimeIntervelCmb.Size = new Size(80, 100);
            TimeIntervelCmb.Items.Add("500");
            TimeIntervelCmb.Items.Add("1000");
            TimeIntervelCmb.Items.Add("2000");
            TimeIntervelCmb.Items.Add("3000");
            TimeIntervelCmb.Items.Add("4000");
            TimeIntervelCmb.Items.Add("5000");
            TimeIntervelCmb.Items.Add("6000");

TimeIntervelCmb.SelectedIndexChanged += new EventHandler(TimeIntervel_SelectedIndexChanged);
            this.Controls.Add(TimeIntervelCmb);
}
  private void TimeIntervel_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
               
                
                if (TimeIntervel.SelectedItem  != null)// Object reference not set to an instance of an object.-Error
                {
                    Stimer = int.Parse(TimeIntervel.SelectedItem.ToString());
                }
            }
            catch (Exception ex)
            {

                MessageBox.Show(ex.Message);
            }
        }

我的尝试：



请为我提供解决方案。



private void TimeIntervel_SelectedIndexChanged（object sender，EventArgs e）

{

试试

{





if（TimeIntervel.SelectedItem） ！= null）

{

Stimer = int.Parse（TimeIntervel.SelectedItem.ToString（））;

}

}

catch（例外情况）

{



MessageBox.Show（ex.Message） ;

}

}

What I have tried:

Kindly provide me solution for this.

private void TimeIntervel_SelectedIndexChanged(object sender, EventArgs e)
{
try
{


if (TimeIntervel.SelectedItem != null)
{
Stimer = int.Parse(TimeIntervel.SelectedItem.ToString());
}
}
catch (Exception ex)
{

MessageBox.Show(ex.Message);
}
}

推荐答案

您尝试处理

private ComboBox TimeIntervel;

但你创建了一个另一个，并且未填充 TimeIntervel 。将 TimeIntervel 重命名为 TimeIntervelCMB

but instead you have created another one, and the TimeIntervel is not populated. Rename the TimeIntervel to TimeIntervelCMB

private ComboBox TimeIntervelCMB;
int Stimer; 
public void set control()
{
   ComboBox TimeIntervelCmb = new ComboBox();
 
            TimeIntervelCmb.Location = new Point(50,70);
            TimeIntervelCmb.Name = "ComboBoxTime";
            TimeIntervelCmb.Size = new Size(80, 100);
            TimeIntervelCmb.Items.AddRange({500,1000,2000,3000,4000,5000,6000});

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