无法在gridview C# aspnet上进行搜索

// 在aspx文件中的gridview标签内添加以下属性
AllowSorting="True" AllowFiltering="True" AutoGenerateColumns="True" OnRowDataBound="GridView1_RowDataBound"

// 在aspx.cs文件中添加以下代码
protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.Header)
    {
        foreach (TableCell cell in e.Row.Cells)
        {
            // 添加筛选输入框
            TextBox txtSearch = new TextBox();
            txtSearch.Attributes["placeholder"] = "搜索";
            txtSearch.Attributes["style"] = "width: 100%";
            txtSearch.Attributes["onkeyup"] = "FilterGrid('" + GridView1.ClientID + "', this)";
            cell.Controls.Add(txtSearch);
        }
    }
}

// 添加JavaScript函数
function FilterGrid(gridId, textBox) {
    var grid = document.getElementById(gridId);
    var rows = grid.getElementsByTagName("tr");

    for (var row = 1; row < rows.length; row++) {
        var displayRow = false;
        var cells = rows[row].getElementsByTagName("td");

        for (var cell = 0; cell < cells.length; cell++) {
            if (cells[cell].innerHTML.toUpperCase().indexOf(textBox.value.toUpperCase()) > -1) {
                displayRow = true;
                break;
            }
        }

        rows[row].style.display = displayRow ? "" : "none";
    }
}