Combobox动态添加行并从SQL Server存储过程下拉

Question

This is basically a search tool. When I type some thing in a combobox, the combobox drops down and will show me suggestions (something like Google search bar)

I created a procedure which does some complex calculations, which take one parameter and returns some rows. Then I created a combobox event (On Update Text).

And in the event handler I wrote this code:

private void combobox_TextUpdate(object sender, EventArgs e)
{
    this.combobox.Items.Clear();
    DataTable List = new DataTable();
    if (this.combobox.Text.Length > 0)
    {
        List = searchIt(combobox.text);
        foreach (DataRow Row in List.Rows)
        {
            this.combobox.Items.Add(Row.ItemArray.GetValue(0).ToString());
        }
        this.combobox.DroppedDown = true;
    }
}

static public DataTable searchIt(string STR)
{
    string connectionString = McFarlaneIndustriesPOSnamespace.Properties.Settings.Default.McFarlane_IndustriesConnectionString;
    SqlConnection con = new SqlConnection(connectionString);
    DataTable DT = new DataTable();
    con.Open();
    SqlDataAdapter DA = new SqlDataAdapter("USE [McFarlane Industries] " +
                                               "EXEC search " + 
                                                STR, connectionString);
    DA.Fill(DT);
    con.Close();
    return DT;
}

The function searchIt executes the stored procedure and it returns a DataTable . The stored procedure is working fine in SQL Server Management Studio.

But in the application it is not working correctly in some cases.

When I type [space] , then it throws an exception and it says stored procedure needs parameter which is not provided.

There are many other characters when I type them it throws exception that invalid character at end of string "my string".

Any suggestion how could I achieve my goal.

Answer 1

Call your stored procedure with sqlcommand to fill your datatable

using (SqlConnection scn = new SqlConnection(connect)
{    
    SqlCommand spcmd = new SqlCommand("search", scn);

    spcmd.Parameters.Add("@blah", SqlDbType.VarChar, -1); //or SqlDbType.NVarChar

    spcmd.CommandType = System.Data.CommandType.StoredProcedure;

    using (SqlDataAdapter da = new SqlDataAdapter(spcmd)) 
    { 
        da.Fill(dt); 
    } 
}

Answer 2

static public DataTable searchIt(string STR)
{
    string connectionString =  McFarlaneIndustriesPOSnamespace.Properties.Settings.Default.McFarlane_IndustriesConnectionString;
    SqlConnection con = new SqlConnection(connectionString);
    DataTable DT = new DataTable();
    con.Open();
    SqlCommand command = new SqlCommand("Name_of_Your_Stored_Procedure",con);
    command.CommandType=CommandType.StoredProcedure;
    command.Parameters.Add(new SqlParameter("@parameter_name",SqlDbType.NVarChar));
    command.Parameters[0].Value="Your Value in this case STR";
    SqlDataAdapter DA = new SqlDataAdapter(command);
    DA.Fill(DT);
    con.Close();
    return DT;
}

Important : 'parameter_Name' and 'Name_of_Your_Stored_Procedure' should be replaced by yours which you have in database. And value of parameter could be like "abc" (combox.Text)

Command and its type, its text are necessary. Adding parameters depends upon your stored procedure. They can be 0,1 or more but once they are added their values must be given. conn(connection) can be passed to new SqlCmmand() or new SqlDataAdapter()

No need of things like 'use' and 'exec'

Following me and this link might be helpful in future for stored procedures http://www.codeproject.com/Articles/15403/Calling-Stored-procedures-in-ADO-NET

Two optional Suggestions for you

1. use variable name 'list' instead of 'List' (you used) however you will not get problem with this name until you add a namespace using System.Collections.Generic; but you may need to use this namespace in future.

2. Use only list.Rows[0].ToString(); no need to get itemarray then get value when you are working with data in strings;