從數據庫中檢索一些數據

Question

我想從數據庫中檢索一些數據，但是我遇到了問題

private void BindGrid()
{
    string constr = ConfigurationManager.ConnectionStrings["homeworkConnectionString2"].ConnectionString;

    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = "select Id, FileName, Date from tblFiles where CourseName LIKE '%' + TextBox3.Text + '%'"; ;
            cmd.Connection = con;
            con.Open();

            GridView1.DataBind();
            con.Close();
        }
    }
}

文本框3具有該數據

因此，我要感謝的問題是“ LIKE”嗎？

我將其更改為：

private void BindGrid()
{
    string likeCondition = string.Empty;
    string textBoxContent = TextBox3.Text;
    var splittedContents = textBoxContent.Split(',').ToList();
    int index = 0;

    foreach (var splittedContent in splittedContents)
    {
        likeCondition += "CourseName LIKE %" + splittedContent + "%";
        index++;

        if (index != splittedContent.Length)
            likeCondition += " OR ";
    }

    string constr = ConfigurationManager.ConnectionStrings["homeworkConnectionString2"].ConnectionString;

    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = "select Id, FileName, Date from tblFiles where " + likeCondition; ; 
            cmd.Connection = con;
            con.Open();
            GridView1.DataBind();
            con.Close();
        }
    }
}

但它仍然無法正常工作-我該怎么辦？

Answer 1

cmd.CommandText = "select Id, FileName, Date from tblFiles where CourseName LIKE '%' + TextBox3.Text + '%'"

您的字符串使用文字文本框名稱。

你想要類似的東西

cmd.CommandText = "select Id, FileName, Date from tblFiles where CourseName LIKE '%" + TextBox3.Text + "%'"

但是，使用參數化查詢會更好

Answer 2

cmd.CommandText = "select Id,Name from tblName where Name LIKE '%" + TextBox1.Text + "%'"

Answer 3

您需要針對拆分您的TextBox3內容,並構建您的整體條件。

我會以以下方式做到這一點：

            string likeCondition = string.Empty;
            string textBoxContent = "Programming1,Database";// use TextBox3.Text here
            var splittedContents = textBoxContent.Split(',').ToList();
            int index = 0;
            foreach (var splittedContent in splittedContents)
            {

                likeCondition += "CourseName LIKE %" + splittedContent + "%";
                index++;
                if (index != splittedContent.Length)
                    likeCondition += " OR ";

            }

現在，您應該通過以下方式在查詢中使用上述likeCondition ：

cmd.CommandText = "select Id, FileName, Date from tblFiles where " + likeCondition; ;