In Fost v. Superior Court (2000) 80 Cal.App.4th 724, the Court has emphasized the importance of cross-examination: "'Cross-examination of a witness is a matter of right.'" "'Prejudice ensues from a denial of the opportunity to place the witness in his proper setting and put the weight of his testimony and his credibility to a test, without which the jury cannot fairly appraise them. To say that prejudice can be established only by showing that the cross-examination, if pursued, would necessarily have brought out facts tending to discredit the testimony in chief, is to deny a substantial right and withdraw one of the safeguards essential to a fair trial. '" (Id. at p. 733.) "Where a witness refuses to submit to cross-examination . . . the conventional remedy is to exclude the witness's testimony on direct. As stated in Witkin: 'In either a civil or criminal case, where a party is deprived of the benefits of cross-examination of a witness by refusal of the witness to answer, the trial court may strike out the direct examination. ' (3 Witkin, Cal. Evidence (3d ed. 1986) 1877, p. 1831, ). This rule applies even 'where the refusal to answer is based on a valid claim of privilege.' (Ibid.) Where a witness refuses to submit to proper cross-examination regarding material issues, the striking out or partial striking out of direct testimony is common, and has been allowed even where the result was to deprive a criminal defendant of the fundamental constitutional right to testify in his own behalf. Striking a witness's entire testimony is, of course, a 'drastic solution,' only to be employed 'after less severe means are considered.' " (Fost, supra, 80 Cal.App.4th at pp. 735-736.) The court further explained: "The logic of this rule applies as much to the situation in which the person who refuses to disclose is a defense witness as to that in which it is the defendant himself, as the refusal of a defense witness to submit to proper cross-examination may corrupt the factfinding process as much as the refusal to submit of the defendant himself." (Id. at p. 736.)