检索特定ID时有些疑问 [英] Some doubt in retrive the particular id

问题描述

I DESIGN如下所示的小应用程序；

项目ID Combobox1
项目名称Textbox1
评价Textbox2
单位文本框3
Amt Textbox4

所有数据都存储在数据库中.

我在文本框中有一个文本框和一个按钮(按钮名称Project Wise Id)，我键入字母R仅以R开头的项目ID想要显示输出，如下所示:

项目ID项目名称费率单位Amt
R001嵌入式30 16480
R002嵌入式40 16 640
1120

项目ID项目名称费率单位Amt
P001 JAVA 15 5 75
P002 .Net 20 10 200
R001嵌入式30 16480
R002嵌入式40 16 640
总计1395

I DESIGN A small application as follows;

Project ID Combobox1
Project Name Textbox1
Rate Textbox2
Unit Textbox3
Amt Textbox4

all the datas are stored in the database.

I have one textbox and one button(button name Project Wise Id)in textbox i type the letter R Only the project id start with R want to display the output as follows;

Project ID Project Name Rate Unit Amt
R001 Embedded 30 16 480
R002 Embedded 40 16 640
1120

Project ID Project Name Rate Unit Amt
P001 JAva 15 5 75
P002 .Net 20 10 200
R001 Embedded 30 16 480
R002 Embedded 40 16 640
Total 1395

private void button3_Click(object sender, EventArgs e)
        {
            con = new SqlConnection("Server=(local);initial catalog=master;Trusted_Connection=True");
            con.Open();
            string str = "select * from Project where PojectID like = '" + cb_id.SelectedItem + "'";
            SqlCommand com = new SqlCommand(str, con);
            SqlDataAdapter sqlda = new SqlDataAdapter(com);
            DataSet ds = new DataSet();
            sqlda.Fill(ds, "Project");
            con.Close();

            ReportDocument r1 = new ReportDocument();
            //r1.Load("Full Path of Your Report\Employee.rpt");
            //string path = Server.MapPath("Reports/Service Bill.rpt");
            r1.Load("Reports/ProjectReport.rpt");
            r1.SetDataSource(ds);
            crystalReportViewer1.ReportSource = r1;
            crystalReportViewer1.RefreshReport();
 }

这里的查询如下:从Project中选择*，其中PojectID像=""+ cb_id.SelectedItem +"'';

从上面请更正查询，我对此表示怀疑.

添加了代码块[/编辑]

Here this query as follows: "select * from Project where PojectID like = ''" + cb_id.SelectedItem + "''";

From the above please correct the query i have some doubt.

Code block added[/Edit]

推荐答案

Sql LIKE需要通配符才能有效.在常规搜索中，％"在SQL中等效于"*"，表示匹配任意数量的任何字符"
试试:

Sql LIKE requires wildcard characters to be effective. ''%'' is the Sql equivalent of ''*'' in a normal search, meaning "match any number of any character"
Try:

string str = "select * from Project where PojectID like = '" + cb_id.SelectedItem + "%'";

匹配ComboBox中的以任何开头"的值.

to match "anything starting with" the value in the ComboBox.

private void button3_Click(object sender, EventArgs e)
        {
            con = new SqlConnection("Server=(local);initial catalog=master;Trusted_Connection=True");
            con.Open();
            string str = "select * from Project where PojectID like = '" + cb_id.SelectedItem + "%'";
            SqlCommand com = new SqlCommand(str, con);
            SqlDataAdapter sqlda = new SqlDataAdapter(com);
            DataSet ds = new DataSet();
            sqlda.Fill(ds, "Project");
            con.Close();
 
            ReportDocument r1 = new ReportDocument();
            //r1.Load("Full Path of Your Report\Employee.rpt");
            //string path = Server.MapPath("Reports/Service Bill.rpt");
            r1.Load("Reports/ProjectReport.rpt");
            r1.SetDataSource(ds);
            crystalReportViewer1.ReportSource = r1;
            crystalReportViewer1.RefreshReport();
 }

请在您的SQL语句中使用LIKE或=运算符.
尝试:

Please use either LIKE or = operator in your SQL statement.
Try with:

string str = "select * from Project where PojectID like '" + cb_id.SelectedItem + "%'";

祝您编码愉快！

Happy coding!

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