“object”不包含“Checked”的定义，并且找不到可接受类型为“object”的第一个参数的扩展方法“Checked”(是不是缺少 using 指令或者程

“object”不包含“Checked”的定义，并且找不到可接受类型为“object”的第一个参数的扩展方法“Checked”(是否缺少 using 指令或者程
.cs文件
 protected void cbTitle_CheckedChanged(object cbTitle, EventArgs e)
        {

            if (cbTitle.Checked == false)
                txtTitle.Text = "";
        }
        protected void cbAuthor_CheckedChanged(object cbAuthor, EventArgs e)
        {
            if (cbAuthor.Checked == false)
                txtAuthor.Text = "";
        }
        protected void cbPress_CheckedChanged(object cbPress, EventArgs e)
        {
            if (cbPress.Checked == false)
                txtPress.Text = "";

.aspx文件
<tr>
    <td class="style3">
        <asp:CheckBox ID="cbTitle" runat="server" AutoPostBack="True" Text="按书名查找记录" OnCheckedChanged="cbTitle_CheckedChanged" />
         </td>
          
               <td align="right" class="style5">
                   <asp:Label ID="lblTitle" runat="server" Text="书名"></asp:Label>
               </td>
               <td class="style2">
                   <asp:TextBox ID="txtTitle" runat="server"></asp:TextBox>
               </td>
           </tr>
                                      <br />
                                      <tr>
                                          <td class="style4">
                                              <asp:CheckBox ID="cbAuthor" runat="server" AutoPostBack="True" 
                                                  OnCheckedChanged="cbAuthor_CheckedChanged" Text="按作者查找记录" />
                                          </td>
                                          <td align="right" class="style9">
                                              <asp:Label ID="lblAuthor" runat="server" Text="作者"></asp:Label>
                                          </td>
                                          <td class="style6">
                                              &nbsp;&nbsp;<asp:TextBox ID="txtAuthor" runat="server"></asp:TextBox>
                                          </td>
                                      </tr>                                        
  <br />
                                          <tr>
                                              <td class="style4">
                                                  <asp:CheckBox ID="cbPress" runat="server" AutoPostBack="True" 
                                                      OnCheckedChanged="cbPress_CheckedChanged" Text="按出版社查找记录" />
                                              </td>
                                              <td align="right" class="style9">
                                                  <asp:Label ID="lblPress" runat="server" Text="出版社"></asp:Label>
                                              </td>
                                              <td class="style6">
                                                  <asp:TextBox ID="txtPress" runat="server"></asp:TextBox>
                                              </td>
                                          </tr>
求大神指导！

------解决思路----------------------

引用:

换成 protected void cbTitle_CheckedChanged(CheckBox cbTitle, EventArgs e)
        {

            if (cbTitle.Checked == false)
                txtTitle.Text = "";
        }
编译的时候也会报错！求指导

不是显式转换参数类型，是显式转换变量((CheckBox)cbTitle).Checked == false