string sign = Convert.ToString(scd.ExecuteScalar());出现错误！！

[ls5879167]

代码如下：
protected void GridView1_SelectedIndexChanging(object sender, GridViewSelectEventArgs e)
{

string setting = Convert.ToString(ConfigurationManager.ConnectionStrings["SmallHouseConn"]);
SqlConnection conn = new SqlConnection(setting);
conn.Open();

string id = this.GridView1.DataKeys[e.NewSelectedIndex].Value.ToString();
string sqlstr = "select sign from homerepair where ID=" + id + "";
SqlCommand scd = new SqlCommand(sqlstr, conn);
string sign = Convert.ToString(scd.ExecuteScalar());//这段出错
if (sign =="0")
{
sign ="1";
}
else

{
sign = "0";

}
scd.CommandText = "update homerepair set sign=" + sign + " where id=" + id ;
scd.ExecuteNonQuery();
this.bind();
conn.Close();

}
数据库中的类型是：varchar（）。
vs中错误提示是语法错误

[EnForGrass]

sql语句
string sqlstr = "select sign from homerepair where ID='" + id + "'";

[EnForGrass]

[Quote=引用 1 楼 的回复:]

sql语句
string sqlstr = "select sign from homerepair where ID='" + id + "'";
[/Quote]
这句也要改
scd.CommandText = "update homerepair set sign='" + sign + "' where id='" + id+"'" ;

[ls5879167]

scd.CommandText = "update homerepair set sign='" + sign + " 'where id='" + id "'";
这句话出错了

[EnForGrass]

[Quote=引用 3 楼 的回复:]

scd.CommandText = "update homerepair set sign='" + sign + " 'where id='" + id "'";
这句话出错了
[/Quote]
看我上面的

[ls5879167]

谢谢 好了！