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问题描述
protected void btnSearch_Click(对象发件人,EventArgs e) { SqlConnection con = new SqlConnection(); con.ConnectionString = ConfigurationManager.ConnectionStrings [ constr]。ConnectionString; con.Open(); 尝试 { 字符串 query = select * from news where name like + txtSearch.Text + %'或描述如' + txtSearch.Text + %'; SqlCommand cmd = new SqlCommand(query,con); SqlDataAdapter da = new SqlDataAdapter(cmd); DataSet ds = new DataSet(); da.Fill(ds); con.Close(); gridrecord.DataSource = ds; gridrecord.DataBind(); if (gridrecord.Rows.Count == 0 ) { lblmsg.Visible = true ; lblmsg.Text = 未找到数据; } } catch (例外情况) { } }
解决方案
} catch (Exception ex) { }
这是错的:你吞下任何异常,因此你没有机会摆脱错误。 另外,如果发生异常,你不会关闭连接。我建议使用using指令:
使用(SqlConnection con = new SqlConnection()) { con.ConnectionString = ... etc. }和
if (gridrecord.Rows.Count == 0 ) { lblmsg.Visible = true ; lblmsg.Text = 未找到数据; }在上次失败后查询成功时永远不会重置该标签。
在使用Like Query时更好地使用Trim()来避免空间 string query = 从新闻中选择*,其中名称为 + txtSearch。文字 .Trim()+ %'或描述如 + txtSearch。 Text .Trim()+ %';
protected void btnSearch_Click(object sender, EventArgs e) { SqlConnection con = new SqlConnection(); con.ConnectionString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString; con.Open(); try { string query = "select * from news where name like '" + txtSearch.Text + "%' or description like '" + txtSearch.Text + "%' "; SqlCommand cmd = new SqlCommand(query, con); SqlDataAdapter da = new SqlDataAdapter(cmd); DataSet ds = new DataSet(); da.Fill(ds); con.Close(); gridrecord.DataSource = ds; gridrecord.DataBind(); if (gridrecord.Rows.Count == 0) { lblmsg.Visible = true; lblmsg.Text = " No data found"; } } catch (Exception ex) { } } 解决方案 } catch (Exception ex) { }
That's wrong: you swallow any exception, hence you have no chance to get rid of the error. Also, you do not close the connection in case of an exception. I suggest a using directive:
using(SqlConnection con = new SqlConnection()) { con.ConnectionString = ... etc. }And
if (gridrecord.Rows.Count == 0) { lblmsg.Visible = true; lblmsg.Text = " No data found"; }will never reset that label when a query succeeds after a previous failure.
better you use Trim() to Avoid Space while using Like Query string query = "select * from news where name like '" + txtSearch.Text.Trim() + "%' or description like '" + txtSearch.Text.Trim() + "%' ";更多推荐
这个搜索查询有什么问题?
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