我编的C#程序有点问题，请高手指点一下

namespace xs{
public partial class shangpinxinxichaxun : Form
{
public DataSet facNumSet = new DataSet();
public shangpinxinxichaxun()
{
InitializeComponent();
}
private void SelspNum_load(object sender, System.EventArgs e)
{
try
{
SqlConnection thisConnection = new SqlConnection("Data Source=PC-200811012150\\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=销售信息管理表");
thisConnection.Open();

SqlDataAdapter FacNumAdapter = new SqlDataAdapter();
FacNumAdapter.SelectCommand.CommandText="Select * from shangpinxinxi";
FacNumAdapter.SelectCommand.Connection=thisConnection;
FacNumAdapter.Fill(facNumSet, "TableName");
DataGridTableStyle fn=new DataGridTableStyle();
fn.AlternatingBackColor=Color.Blue;
fn.MappingName=facNumSet.DataSetName;
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
finally
{
}
}

private void button1_Click(object sender, EventArgs e)
{

string condition = "";
if (this.textBox1.Text.Trim() != "")
{
condition += "商品编号 like '%'+textBox1.Text.Trim()+'%'";
if (this.textBox2.Text.Trim() != "")
{
condition += "and 商品名称 like '%' + textBox2.Text.Trim()+'%'";
}
}
else
{
if (this.textBox2.Text.Trim() != "")
{
condition += "商品名称 like '%' + textBox2.Text.Trim()+'%'";
}
else
{
MessageBox.Show("请输入查询条件", "错误");
return;
}
}
//////////////////////////////////////////////////////////
DataView myDV = new DataView(facNumSet.Tables["TableName"]);
myDV.RowFilter = condition;

this.dataGridView1.DataSource = myDV;
///////////////////////////////////////////
if (this.dataGridView1.RowCount== 1)
{
MessageBox.Show("对不起，货品中没有与您检索条件相匹配的记录!");
return;
}
this.textBox1.Clear();
this.textBox2.Clear();
}

这是一个产品信息查询的模块，运行时myDV.RowFilter = condition;处总提示“表达式包含未定义的函数调用 textBox2.Text.Trim()。”这到底是哪的问题啊？？？