c# - 你调用的对象是空的。当我运行此代码时出现以下错误，此代码用于检查 gridview 复选框

Question

protected void Button1_Click(object sender, EventArgs e)
{       
    for (int i = 0; i < GridView1.Rows.Count; i++)
    {
        CheckBox ch = (CheckBox)GridView1.FindControl("chkid");

        if (ch.Checked)
        {
            Response.Write("ch= true");
            Label1.Text = GridView1.Rows.ToString();
        }
        else
            Response.Write("ch= false");
    }                 
 }

Answer 1

更正这条线。

CheckBox ch = (CheckBox)GridView1.Rows[i].FindControl("chkid");

Answer 2

在使用复选框之前简单地做一个空检查

protected void Button1_Click(object sender, EventArgs e)
{       
    for (int i = 0; i < GridView1.Rows.Count; i++)
    {
        CheckBox ch = (CheckBox)GridView1.FindControl("chkid");

        if (ch != null)
        {
            if (ch.Checked)
            {
                Response.Write("ch= true");
                Label1.Text = GridView1.Rows.ToString();
            }
            else
                Response.Write("ch= false");
        }
    }                 
 }