我从没做过，但是您能为文本框添加一个EventHandler吗?

I have never done that, but could you just add an EventHandler for the Textbox?

<asp:TextBox runat="server" OnTextChanged="Text_OnTextChanged" ID="Text"></asp:TextBox>

在CodeBehind中，您可以仅使用发送方来获取文本:

In the CodeBehind you can just use the sender to get the Text:

protected void TextBox1_TextChanged(object sender, EventArgs e)
{
  TextBox text = sender as TextBox;
  text.Text; //this is the text.
}

虽然这看起来像实际的代码，但这是未经测试的伪代码，仅供说明！

在您澄清后添加:
好的，所以您需要这样做:

While this might look like actual Code, this is untested pseudocode for illustration only!

Added after your clarification:
Ok so you need this:

Sub GridView_RowCommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs){
	Dim index As Integer = Convert.ToInt32(e.CommandArgument)
	Dim row As GridViewRow = GridView.Rows(index)
	TextBox lName = row.FindControl("Lname") as TextBox;
	TextBox fName = row.FindControl("FName") as TextBox;
	Label empId = row.FindControl("EmpId") as Label;
}

假设您所有的控件都在ASP标记id="Lname"中设置了这样的ID.这需要与FindControl的参数完全相同.

希望这会有所帮助，并且不要再有经过检查的代码可能包含错字.

Assuming all your Controls have the id set like this in the ASP Markup id="Lname". This needs to be exactly like the Parameter of FindControl.

Hope this helps, and again no checked code, may contain typos.